Thoughts From a Global Technology Leadership Forum

I recently had the privilege to attend and participate in a global technology leadership forum.  The forum consisted of technology investors, vendors and thought leaders and was an excellent event.  The tracks I focused on were VDI, Big Data, Data Center Infrastructure, Data Center Networks, Cloud and Collaboration.  The following are my notes from the event:

VDI:

There was a lot of discussion around VDI and a track dedicated to it.  The overall feeling was that VDI has not lived up to its hype over the last few years, and while it continues to grow market share it never reaches the predicted numbers, or hits the bubble that is predicted for it.  For the most part the technical experts agreed on the following:

  • VDI has had several hang-ups both technical, cost and image wise that have held it back from mass-scale adoption
  • The technical challenges have been solved for the most part, storage solutions like cache, tiering and SSD can solve the IOPS contention and help to reduce the costs.  Storage optimization products like Atlantis Computing also exist to alleviate costs per seat by reducing storage requirements to obtain acceptable IOPS.
  • The cost model is getting better but is still not at a place where VDI is a no-brainer.  The consensus was that until a complete VDI solution can be rolled out for a cost per seat equal or lower to a typical enterprise desktop/laptop it will still be a tough decision.  Currently VDI is still a soft cost ROI as in it provides added features and benefit at a slightly higher cost.

There was some disagreement on whether VDI is the right next step for the enterprise.  The split I saw was nearly 50/50 with half thinking it is the way forward and will be deployed in greater and greater scale, and the other half thinking it is one of many viable current solutions and may not be the right 3-5 year goal.  I’ve expressed my thoughts previously: http://www.definethecloud.net/vdi-the-next-generation-or-the-final-frontier. Lastly we agreed that the key leaders in this space are still VMware and Citrix.  While each have pros and cons it was believed that both solutions are close enough as to be viable and that VMware’s market share and muscle make it very possible to pull into a dominant lead.  Other players in this space were complete afterthoughts.

Big Data:

Let me start by saying I know nothing about big data.  I sat in these expert sessions to understand more about it, and they were quite interesting.  Big data sets are being built, stored, and analyzed.  Customer data, click traffic, etc. are being housed to gather all types of information and insight.  Hadoop clusters are being used for processing data, cloud storage such as Amazon S3 is being utilized as well as on-premises solutions.  The main questions were in regard to where the data should be stored and where it should be processed, as well as the compliance issues that may arise with both.  Another interesting question was the ability to leave the public cloud if your startup turns big enough to beat the costs of public cloud with a private one.  For example if you have a lot of data you can mail Amazon disks to get it into S3 faster than WAN speed, but to our knowledge they can’t/won’t mail your disk back if you want to leave.

Data Center Infrastructure:

Overall there was an agreement that very few data center infrastructure (defined here as compute, network, storage) conversations occur without chat about cloud.  Cloud is a consideration for IT leaders from the SMB to large global enterprise.  That being said while cloud may frame the discussion the majority of current purchases are still focused on consolidation and virtualization, with some automation sprinkled in.  Private-cloud stacks from the major vendors also come into play helping to accelerate the journey, but many are still not true private clouds (see: http://www.definethecloud.net/the-difference-between-private-cloud-and-converged-infrastructure.)

Data Center Networks:

I moderated a session on flattening the data center networks, this is currently referred to as building ‘fabrics.’  The majority of the large network players have announced or are shipping ‘fabric’ solutions.  These solutions build multiple active paths at Layer 2 alleviating the blocked links traditional Spanning-Tree requires.  This is necessary as we converge our data and ask more of our networks.  The panel agreed that these tools are necessary but that standards are required to push this forward and avoid vendor lock-in.  As an industry we don’t want to downgrade our vendor independence to move to a Fabric concept.  That being said most agree that pre-standard proprietary deployments are acceptable as long as the vendor is committed to the standard and the hardware is intended to be standards compliant.

Cloud:

One of the main discussions conversations I had was in regards to PaaS.  While many agree that PaaS and SaaS are the end goals of public and private clouds, the PaaS market is not yet fully mature (see: http://www.networkcomputing.com/private-cloud/231300278.)  Compatibility, interoperability and lock-in were major concerns overall for PaaS.  Additionally while there are many PaaS leaders, the market is so immature leadership could change at any time, making it hard to pick which horse to back. 

Another big topic was open and open source.  Open Stack, Open Flow and open source players like RedHat.  With RedHat’s impressive YoY growth they are tough to ignore and there is a lot of push for open source solutions as we move to larger and larger cloud systems.  The feeling is that larger and more technically adept IT shops will be looking to these solutions first when building private clouds.

Collaboration:

Yet another subject I’m not an expert on but wanted to learn more about.  The first part of the discussion entailed deciding what we were discussing i.e. ‘What is collaboration.’  With the term collaboration encompassing: voice, video, IM, conferencing, messaging, social media, etc. depending on who you talk to this was needed.  We settled into a focus on enterprise productivity tools, messaging, information repositories, etc.  The overall feeling was that there are more questions than answers in this space.  Great tools exist but there is no clear leaders.  Additionally integration between enterprise tools and public tools was a topic and involved the idea of ensuring compliance.  One of the major discussions was building internal adoption and maintaining momentum.  The concern with a collaboration tool rollout is the initial boom of interest followed by a lull and eventual death of the tool as users get bored with the novelty before finding any ‘stickiness.’

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Why FCoE Standards Matter

Mike Fratto at Network Computing recently wrote an article titled ‘FCoE: Standards Don’t Matter; Vendor Choice Does’ (http://www.networkcomputing.com/storage-networking-management/231002706.)

I definitely differ from Mike’s opinion on the subject.  While I’m no fan of the process of making standards (puts sausage making to shame), or the idea of slowing progress to wait on standards, I do feel they are an absolutely necessary part of FCoE’s future.  It’s all about the timing at which we expect them, the way in which they’re written, and most importantly the way in which they’re adhered to.

Mike bases his opinion on Fibre Channel history and accurately describes the strangle hold the storage vendors have had on the customer.  The vendor’s Hardware Compatibility List (HCL) dictates which vendor you could connect to, and which model and which firmware you can use.  Slip off the list and you lose support.  This means that in the FC world customers typically went with the Storage Area Network (SAN) their VAR or storage vendor recommended, and stuck with it.  While not ideal this worked fine in the small network environment of SAN with the specialized and dedicated purpose of delivering block data from array to server.  These extreme restrictions based on storage vendors and protocol compatibility will not fly as we converge networks.

As worried as storage/SAN admins may be about moving their block data onto Ethernet networks, the traditional network admins may be more worried because of the interoperability concept.  For years network admins have been able to intermix disparate vendors technology to build the networks that they desired, best-of-breed or not.  A load-balancer here, firewall there, data center switch here and presto everything works.  They may have had to sacrifice some features (proprietary value add-that isn’t compatible) but they could safely connect the devices.  More importantly they didn’t have to answer to an HCL dictated by some end-point (storage disk) or another on their network.

For converged networking to work, this freedom must remain.  Adding FCoE to consolidate infrastructure cannot lock network admins into storage HCLs and extreme hardware incompatibility.  This means that the standards must exist, be agreed upon, be specific enough, and be adhered to.  While Mike is correct, you probably won’t want to build multi-vendor networks day one, you will want to have the opportunity to incorporate other services, and products, migrate from one vendor to another, etc.  You’ll want an interoperable standard that allows you to buy 3rd party FCoE appliances for things like de-duplication, compression, encryption or whatever you may need down the road.  We’re not talking about building an Ethernet network dedicated to FCoE, we’re talking about building one network to rule them all (hopefully we never have to take it to Mordor and toss it into molten lava.)  To run one network we need the standards and compatibility that provide us flexibility.

There is no reason for storage vendors to hold the keys to what you can deploy any longer.  Hardware is stable, and if standards are in place the network will properly transport the blocks.  Customers and resellers shouldn’t accept lock in and HCL dictation just because that has been the status quo.  We’re moving the technology forward move your thinking forward.  The issue in the past has been the looseness with which IEEE FCBB-5 is written on some aspects since it’s inception.  This leaves room for interpretation which is where interoperability issues arise between vendors who are both ‘standards based.’  The onus is on us as customers, resellers and an IT community to demand that the standards be well defined, and that the vendors adhere to them in an interoperable fashion. 

Do not accept incompatibility and lack of interoperability in your FCoE switching just because we made the mistake of allowing that to happen with pure FC SANs.  Next time your storage vendor wants a few hundred thousand for your next disk array tell them it isn’t happening unless you can plug it into any standards compliant network without fear of their HCL and loss of support.

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Why NetApp is my ‘A-Game’ Storage Architecture

One of, if not the, most popular of my blog posts to date has been ‘Why Cisco UCS is my ‘A-Game’ Server Architecture (http://www.definethecloud.net/why-cisco-ucs-is-my-a-game-server-architecture.)  In that post I describe why I lead with Cisco UCS for most consultative engagements.  This follow up for storage has been a long time coming, and thanks to some ‘gentle’ nudging and random coincidence combined with an extended airport wait I’ve decided to get this posted.

If you haven’t read my previous post I take the time to define my ‘A-Game’ architectures as such:

“The rule in regards to my A-Game is that it’s not a rule, it’s a launching point. I start with a specific hardware set in mind in order to visualize the customer need and analyze the best way to meet that need. If I hit a point of contention that negates the use of my A-Game I’ll fluidly adapt my thinking and proposed architecture to one that better fits the customer. These points of contention may be either technical, political, or business related:

  • Technical: My A-Game doesn’t fit the customers requirement due to some technical factor, support, feature, etc.
  • Political: My A-Game doesn’t fit the customer because they don’t want Vendor X (previous bad experience, hype, understanding, etc.)
  • Business: My A-Game isn’t on an approved vendor list, or something similar.

If I hit one of these roadblocks I’ll shift my vendor strategy for the particular engagement without a second thought. The exception to this is if one of these roadblocks isn’t actually a roadblock and my A-Game definitely provides the best fit for the customer I’ll work with the customer to analyze actual requirements and attempt to find ways around the roadblock.

Basically my A-Game is a product or product line that I’ve personally tested, worked with and trust above the others that is my starting point for any consultative engagement.

In my A-Game Server post I run through my hate then love relationship that brought me around to trust, support, and evangelize UCS; I cannot express the same for NetApp.  My relationship with NetApp fell more along the lines of love at first sight.

NetApp – Love at first sight:

I began working with NetApp storage at the same time I was diving headfirst into datacenter as a whole.  I was moving from server admin/engineer to architect and drinking from the SAN, Virtualization, and storage firehouse.  I had a fantastic boss who to this day is a mentor and friend that pushed me to learn quickly and execute rapidly and accurately, thanks Mike!  The main products our team handled at the time were: IBM blades/servers, VMware, SAN (Brocade and Cisco) and IBM/NetApp storage.  I was never a fan of the IBM storage.  It performed solidly but was a bear to configure, lacked a rich feature set and typically got put in place and left there untouched until refresh.  At the same time I was coming up to speed on IBM storage I was learning more and more about NetApp.

From the non-technical perspective NetApp had accessible training and experts, clear value-proposition messaging and a firm grasp on VMware, where virtualization was heading and how/why it should be executed on.  This hit right on with what my team was focused on.  Additionally NetApp worked hard to maintain an excellent partner channel relationship, make information accessible, and put the experts a phone call or flight away.  This made me WANT to learn more about their technology.

The lasting bonds:

Breakfast food, yep breakfast food is what made NetApp stick for me, and still be my A-game four years later. Not just any breakfast food, but a personal favorite of mine; beer and waffles, err, umm… WAFL (second only to chicken and waffles and missing only bacon.)  Data ONTAP (the beer) and NetApp’s Write Anywhere File System (WAFL) are at the heart of why they are my A-Game.  While you can find dozens of blogs, competitive papers, etc. attacking the use of WAFL for primary block storage, what WAFL enables is amazing from a feature perspective, and the performance numbers NetApp can put up speak for themselves.  Because, unlike a traditional block based array, NetApp owns the underlying file system they can not only do more with the data, but they can more rapidly adapt to market needs with software enhancements.  Don’t take my word for it, do some research, look at the latest announcements from other storage leaders and check to see what year NetApp announced their version of those same features, with few exceptions you’ll be surprised.  The second piece of my love for NetApp is Data ONTAP.  NetApp has several storage controller systems ranging from the lower end to the Tier-1 high-capacity, high availability systems.  Regardless of which one you use, you’re always using the same operating/management system, Data ONTAP.  This means that as you scale, change, refresh, upgrade, downgrade, you name it, you never have to retrain AND you keep a common feature set.

My love for breakfast is not the only draw to NetApp, and in fact without a bacon offering I would have strayed if there weren’t more (note to NetApp: Incorporate fatty pork the way politicians do.) 

Other features that keep NetApp top of my list are:

  • Primary block-level storage Deduplication with real world savings at 70+ % with minimal performance hit (and no license fee to boot)
  • Ease of upgrade/downgrade (keep the shelves of disks, replace the controllers, data stays)
  • Read/Write ‘0’ space/cost clones (the ability to clone various data sets in a read/write status using only pointers and storing only the change ‘delta’) and FlexClone capabilities as a whole
  • Highly optimized snapshots for point-in-time rollback, test/dev, etc.
  • VMware plugins to enable VMware admins to manage and monitor their own storage allotments
  • Storage virtualization, the ability to carve out storage and the management of that storage to multiple tenants in a similar fashion to what VMware does for servers
  • Ability to get 80% of the performance benefits of a shelf of SSD drives by adding Flash Cache (PAM II) cards 

Add to that more recent features such as first to market with FCoE based storage and you’ve got a winner in my book.  All that being said I still haven’t covered the real reason NetApp is the first storage vendor in my head anytime I talk about storage.

Unification:

Anytime I’m talking about servers I’m talking about virtualization as well.  Because I don’t work in the Unix or Mainframe worlds I’m most likely talking about VMware (90% market share has that effect.)  When dealing with virtualization my primary goals are consolidation/optimization and flexibility.  In my opinion nobody can touch NetApp storage for this.  I’m a fan of choice and options, I also like particular features/protocols for particular use cases.  On most storage platforms I have to choose my hardware based on the features and protocols my customers require, and most likely use more than one platform to get them all.  This isn’t the case with NetApp.  With few exceptions every protocol/feature is available simultaneously with any given hardware platform.  This means I can run iSCSI, FC, FCoE or all of the above for block based needs at the same time I run CIFS natively to replace Windows file servers, and NFS for my VMware data stores.  All of that from the same box or even the same ports!  This lets me tier my protocols and features to the application requirements instead of to my hardware limitations.

I’ve been working on VMware deployments in some fashion for four years, and have seen dozens of unique deployments but personally never deployed or worked with a VMware environment that ran off a single protocol, typically at a minimum NFS is used for ISO datastores and CIFS can be used to eliminate Windows file servers rather than virtualize them, with a possible block based protocol involved for boot or databases.

Additionally NetApp offers features and functionality to allow multiple storage functions to be consolidated on a single system.  You no longer require separate hardware for primary, secondary, backup, DR, and archive.  All of this can then be easily setup and managed for replication across any of NetApp’s platforms, or many 3rd party systems front-ended with V-series.  These two pieces combined create a truly ‘unified’ platform.

When do I bring out my B-Game?

NetApp like any solution I’ve ever come across is not the right tool for every job.  For me they hit or exceed the 80/20 rule perfectly.  A few places where I don’t see NetApp as a current fit:

  • Small to Medium Business (SMB) – At the SMB level a single protocol solution may work and you can find lower cost solutions that fit the bill, but if you scale faster than expected you’re stuck with a single protocol platform and may end up having to purchase and manage additional devices if/when needs change
  • Massive scalability – Here I’m talking public cloud petabytes upon petabytes where systems like Isilon from EMC and its competitors have the lead
  • Top-Tier performance and enterprise class reliability for Tier-1 applications –  Here at the very high end typically EMC or Hitachi are the players, and IBM using SVC may also play
  • Mainframes, NetApp don’t play that and Big Blue don’t support it  

Summary:

While I stick to there are no ‘one-size fits all’ IT solutions, and that my A-Game is a starting point not a rule I find NetApp to hit the bulls eye for 80+ percent of the market I work with.  Not only do they fit upfront, but they back it up with support, continued innovation, and product advancement.  NetApp isn’t ‘The Growth Company’ and #2 in storage by luck or chance (although I could argue they did luck out quite a bit with the timing of the industry move to converged storage on 10GE.)

Another reason NetApp still reigns king as my A-Game is the way in which it marries to my A-Game server architecture.  Cisco UCS enables unification, protocol choice and cable consolidation as well as virtualization acceleration, etc.  All of these are further amplified when used alongside NetApp storage which allows rapid provisioning, protocol options, storage consolidation and storage virtualization, etc.  Do you want to pre-provision 50 (or 250) VMware hosts with 25 GB read/write boot LUNs ready to go at the click of a template?  Do you want to do this without utilizing any space up front?  UCS and NetApp have the toolset for you.  You can then rapidly bring up new customers, or stay at dinner with your family while a Network Operations Center (NOC) administrator deploys a pre-architected pre-secured, pre-tested and provisioned server from a template to meet a capacity burst.

If you’re considering a storage decision, a private cloud migration, or a converged infrastructure pod make sure you’re taking a look at NetApp as an option and see it for yourself.  For some more information on NetApp’s virtualization story see the links below:

TR3856: Quantifying the Value of Running VMware on NetApp 

TR3808: VMware vSphere and ESX 3.5 Multiprotocol Performance Comparison Using FC, iSCSI, and NFS

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Intel’s Betting the Storage I/O Farm on the CPU

 

I had the privilege of attending Tech Field Day 4 in San Jose this week as a delegate thanks to Stephen Foskett and Gestalt IT.  It was a great event and a lot of information was covered in two days of presentations.  I’ll be discussing the products and vendors that sponsored the event over the next few blogs starting with this one on Intel.  Check out the official page to view all of the delegates and find links to the recordings etc. http://gestaltit.com/field-day/2010-san-jose/.

Intel presented both their Ethernet NIC and storage I/O strategy as well as a processor update and public road map, this post will focus on the Ethernet and I/O presentation.

Intel began the presentation with an overview of the data center landscape and a description of the move towards converged I/O infrastructure, meaning storage, traditional LAN and potentially High Performance Computing (HPC) on the same switches and cables.  Anyone familiar with me or this site knows that I am a fan and supporter of converging the network infrastructure to reduce overall cost and complexity as well as provide more flexibility to data center I/O so I definitely liked this messaging.  Next was a discussion of iSCSI and its tradition of being used as a consolidation tool.

iSCSI:

iSCSI has been used for years in order to provide a mechanism for consolidated block storage data without the need for a separate physical network.  Most commonly iSCSI has been deployed as a low-cost alternative to Fibre Channel.  Its typically been used in the SMB space and for select applications in larger datacenters.  iSCSI was previously limited to 1 Gigabit pipes (prior to the 10GE ratification) and it also suffers from higher latency and lower throughput than Fibre Channel.  The beauty of iSCSI is the ability to use existing LAN infrastructure and traditional NICs to provide block access to shared disk, the Achilles heal is performance.  Because of this cost has always been the primary deciding factor to use iSCSI. For more information on iSCSI see my post on storage protocols: http://www.definethecloud.net/storage-protocols.

In order to increase the performance of iSCSI and decrease the overhead on the system processor(s) the industry developed iSCSI Host Bus Adapters (HBA) which offload the protocol overhead to the I/O card hardware.  These were not widely adopted due to the cost of the cards, this means that a great deal of iSCSI implementations rely on a protocol stack in the operating system (OS.) 

Intel then drew parallels to doing the same with FCoE via the FCoE software stack available for Windows and included in current Linux kernels.  The issue with drawing this parallel is that iSCSI is a mid-market technology that sacrifices some performance and reliability for cost, whereas FCoE is intended to match/increase the performance and reliability of FC while utilizing Ethernet as the transport.  This means that when looking at FCoE implementations the additional cost of specialized I/O hardware makes sense to gain the additional performance and reduce the CPU overhead.

Intel also showed some performance testing of FCoE software stack versus hardware offload using a CNA.  The IOPS they showed were quite impressive for a software stack, but IOPS isn’t the only issue.  The other issue is protocol overhead on the processor.Their testing showed an average of about 6% overhead for the software stack.  6% is low but we were only being shown one set of test criteria for a specific workload.  Additionally we were not provided the details of the testing criteria.  Other tests I’ve seen of the software stack are about 2 years old and show very comparable CPU utilization for FCoE software stack and Generation I CNAs for 8 KB reads, but a large disparity as the block size increased (CPU overhead became worse and worse for the software stack.)  In order to really understand the implications of utilizing a software stack Intel will need to publish test numbers under multiple test conditions:

  • Sequential and random
  • Various read and write combinations
  • Various block sizes
  • Mixed workloads of FCoE and other Ethernet based traffic

I’ve since located the test Intel referenced from Demartek.  It can be obtained here (http://www.demartek.com/Reports_Free/Demartek_Intel_10GbE_FCoE_iSCSI_Adapter_Performance_Evaluation_2010-09.pdf.)  Notice that in the forward Demartek states the importance of CPU utilization data and stresses that they don’t cherry pick data then provides CPU utilization data only for the Microsoft Exchange simulation through JetStress, not for the SQLIO simulation at various block sizes.  I find that you can learn more from the data not shown in vendor sponsored testing, than the data shown.

Even if we were to make two big assumptions: Software stack IOPS are comparable to CNA hardware, and additional CPU utilization is less than or equal to 6% would you want to add an additional 6% CPU overhead to your virtual hosts?  The purpose of virtualization is to come as close as possible to full hardware utilization via placing multiple workloads on a single server.  In that scenario adding additional processor overhead seems short sighted.

The technical argument for doing this is two fold:

  • Saving cost on specialized I/O hardware
  • Processing capacity evolves faster than I/O offload capacity and speeds mainly due to economies of scale therefore your I/O performance will increase with each processor refresh using a software stack

If you’re looking to save cost and are comfortable with the processor and performance overhead then there is no major issue with using the software stack.  That being said if you’re really trying to maximize performance and or virtualization ratios you want to squeeze every drop you can out of the processor for the virtual machines.  As far as the second point of processor capacity goes, it most definitely rings true but with each newer faster processor you buy you’re losing that assumed 6% off the top for protocol overhead.  That isn’t acceptable to me.

The Other Problem:

FC and FCoE have been designed to carry native SCSI commands and data and treat them as SCSI expects, most importantly frames are not dropped (lossless network.)  The flow control mechanism FC uses for this is called buffer-to-buffer credits (B2B.)  This is a hop-to-hop mechanism implemented in hardware on HBAs/CNAs and FC switches.  In this mechanism when two ports initialize a link they exchange a number of buffer spaces they have dedicated to the device on the other side of the link based on agreed frame size. When any device sends a frame it is responsible for keeping track of the buffer space available on the receiving device based on these credits.  When a device receives a frame and has processed it (removing it from the buffer) it returns an R_RDY similar to a TCP ACK which lets the sending device know that a buffer has been freed.  For more information on this see the buffer credits section of my previous post: http://www.definethecloud.net/whats-the-deal-with-quantized-congestion-notification-qcn.  This mechanism ensures that a device never sends a frame that the receiving device does not have sufficient buffer space for and this is implemented in hardware. 

On FCoE networks we’re relying on Ethernet as the transport so B2B credits don’t exist.  Instead we utilize Priority Flow Control (PFC) which is a priority based implementation of 802.3x pause.  For more information on DCB see my previous post: http://www.definethecloud.net/data-center-bridging-exchange.  PFC is handled by DCB capable NICs and will handle sending a pause before the NIC buffers overflow.  This provides for a lossless mechanism that can be translated back into B2B credits at the FC edge. 

The issue here with the software stack is that while the DCB capable NIC ensures the frame is not dropped on the wire via PFC it has to pass processing across the PCIe bus to the processor and allow the protocol to be handled by the OS kernel.  This adds layers in which the data could be lost or corrupted that don’t exist with a traditional HBA or CNA.

Summary:

FCoE software stack is not a sufficient replacement for a CNA.  Emulex, Broadcom, Qlogic and Brocade are all offloading protocol to the card to decrease CPU utilization and increase performance.  HP has recently announced embedding Emulex OneConnect adapters, which offload iSCSI, TCP and FCoE, on the system board.  That’s a lot of backing for protocol offload with only Intel standing on the other side of the fence.  My guess is that Intel’s end goal is to sell more processors, and utilizing more cycles for protocol processing makes sense.  Additionally Intel doesn’t have a proven FC stack to embed on a card and the R/D costs would be significant, so throwing it in the kernel and selling their standard NIC makes sense to the business.  Lastly don’t forget storage vendor qualification, Intel has an uphill battle getting an FCoE software stack on the approved list for the major storage vendors.

Full Discloser:  Tech Field Day is organized by the folks at Gestalt IT and paid for by the presenters of the event.  My travel, meals and accommodations were paid for by the event but my opinions negative or positive are all mine.

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The Brocade FCoE Proposition

I recently realized that I, like a lot of the data center industry, have completely forgotten about Brocade recently.  There has been little talked about on their FCoE front, Fibre Channel Front, or CNAs.  Cisco and HP have been dominating social media with blade and FCoE battles, but I haven’t seen much coming from Brocade.  I thought it was time to take a good look.

The Brocade Portfolio:

Brocade 1010 and 1020 CNAs The Brocade 1010 (single port) and Brocade 1020 (dual port) Converged Network Adapters (CNAs) integrate 10 Gbps Ethernet Network Interface Card (NIC) functionality with Fibre Channel technology—enabling transport over a 10 Gigabit Ethernet (GbE) connection through the new Data Center Bridging (DCB) and Fibre Channel over Ethernet (FCoE) protocols, providing best-in-class LAN connectivity and I/O consolidation to help reduce cost and complexity in next-generation data center environments.
Brocade 8000 Switch The Brocade 8000 is a top-of-rack link layer (Layer 2) CEE/FCoE switch with 24 10 Gigabit Ethernet (GbE) ports for LAN connections and eight Fibre Channel ports (with up to 8 Gbps speed) for Fibre Channel SAN connections. This reliable, high-performance switch provides advanced Fibre Channel services, supports Ethernet and CEE capabilities, and is managed by Brocade DCFM.
Brocade FCOE10-24 Blade The Brocade FCOE10-24 Blade is a Layer 2 blade with cut-though non-blocking architecture designed for use with Brocade DCX and DCX-4S Backbones. It features 24 10 Gbps CEE ports and extends CEE/FCoE capabilities to Brocade DCX Backbones, enabling end-of-row CEE/FCoE deployment. By providing first-hop connectivity for access layer servers, the Brocade FCOE10-24 also enables server I/O consolidation for servers with Tier 3 and some Tier 2 applications.

Source: http://www.brocade.com/products-solutions/products/index.page?dropType=Connectivity&name=FCOE

The breadth of Brocade’s FCoE portfolio is impressive when compared to the other major players: Emulex and Qlogic with CNAs, HP with FlexFabric for C-Class and H3C S5820X-28C Series ToR, and only Cisco providing a wider portfolio with an FCoE and virtualization aware I/O card (VIC/Palo), blade switches (Nexus 4000), ToR/MoR switches (Nexus 5000), and an FCoE Blade for the Nexus 7000.  This shows a strong commitment to the FCoE protocol on Brocade’s part, as does there participation on the standards body.

Brocade also provides a unique ability to standardize on one vendor from the server I/O card, through the FCoE network to the Fibre Channel (FC) core switching.  Additionally using the 10-24 blade customers can collapse the FCoE edge into their FC core providing a single hop collapsed core mixed FCoE/FC SAN.  That’s a solid proposition for a data center with a heavy investment in FC and a port count low enough to stay within a single chassis per fabric.

But What Does the Future Hold?

Before we take a look at where Brocade’s product line is headed, let’s look at the purpose of FCoE.  FCoE is designed as another tool in the data center arsenal for network consolidation.  We’re moving away from the cost, complexity and waste of separate networks and placing our storage and traditional LAN data on the same infrastructure.  This is similar to what we’ve done in the past in several areas, on mainframes we went from ESCON to FICON to leverage FC, our telephones went from separate infrastructures to IP based, we’re just repeating the same success story with storage.  The end goal is everything on Ethernet.  That end goal may be sooner for some than others, it all depends on comfort level, refresh cycle, and individual environment.

If FCoE is a tool for I/O consolidation and Ethernet is the end-goal of that, then where is Brocade heading?

This has been my question since I started researching and working with FCoE about three years ago.  As FCoE began hitting the mainstream media Cisco was out front pushing the benefits and announcing products, they were the first on the market with an FCoE switch, the Nexus 5000.  Meanwhile Brocade and others were releasing statements attempting to put the brakes on.  They were not saying FCoE was bad, just working to hold it off.

This makes a lot of sense from both perspectives, the core of Cisco’s business is routing and switching therefore FCoE is a great business proposition.  They’re also one of the only two options for FC switching in the enterprise (Brocade and Cisco) so they have the FC knowledge.  Lastly they had a series of products already in development. 

From Brocade’s and others perspectives they didn’t have products ready to ship, and they didn’t have the breath and depth in Ethernet so they needed time.  The marketing releases tended to become more and more positive towards FCoE as their products launched.

This also shows in Brocade’s product offering, two of the three products listed above are designed to maintain the tie to FC.

Brocade 8000:

This switch has 24x 10GE ports and 8x 8Gbps FC ports.  These ports are static onboard which means that this switch is not for you if:

  • You just need 10GE (iSCSI, NFS, RDMA, TCP, UDP, etc.)
  • You plan to fully migrate to FCoE (The FC ports then go unused.)
  • You only need FCoE, small deployment using FCoE based storage which is available today.

In comparison the competing product is the Nexus 5000 which has a modular design allowing customers to use all Ethernet/DCB or several combinations of Ethernet and FC at 1/2/4/8 Gbps.

Brocade FCoE 10/24 Blade:

This is an Ethernet blade for the DCX Fibre Channel director.  This ties Brocade’s FCoE director capabilities to an FC switch rather than Ethernet switch.  Additionally this switch only supports directly connected FCoE devices which will limit overall scalability.

In comparison the Cisco FCoE blade for the nexus 7000 is a DCB capable line card with FCoE capability by years end.  This merges FCoE onto the network backbone where it’s intended to go.

Summary:

If your purpose in assessing FCoE is to provide a consolidated edge topology for server connectivity tying it back to a traditional FC SAN then Brocade has a strong product suite for you.  If you’re end goal is consolidating the network as a whole then it’s important to seriously consider the purchase of FC based FCoE products.  That’s not to say don’t buy them, just understand what you’re getting, and why you’re getting it.  For instance if you need to tie to a Fibre Channel core now and don’t intend to replace that for 3-5 years then the Brocade 8000 may work for you because it can be refreshed at the same time.

Several options exist for FCoE today and most if not all of them have a good fit.  Assess first what your trying to accomplish and when, then look at the available products and decide what fits best.

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What’s the deal with Quantized Congestion Notification (QCN)

For the last several months there has been a lot of chatter in the blogosphere and Twitter about FCoE and whether full scale deployment requires QCN.  There are two camps on this:

  1. FCoE does not require QCN for proper operation with scale.
  2. FCoE does require QCN for proper operation and scale.

Typically the camps break down as follows (there are exceptions) :

  1. HP camp stating they’ve not yet released a suite of FCoE products because QCN is not fully ratified and they would be jumping the gun.  The flip side of this is stating that Cisco did jumped the gun with their suite of products and will have issues with full scale FCoE.
  2. Cisco camp stating that QCN is not required for proper FCoE frame flow and HP is using the QCN standard as an excuse for not having a shipping product.

For the purpose of this post I’m not camping with either side, I’m not even breaking out my tent.  What I’d like to do is discuss when and where QCN matters, what it provides and why.  The intent being that customers, architects, engineers etc. can decide for themselves when and where they may need QCN.

QCN: QCN is a form of end-to-end congestion management defined in IEEE 802.1.Qau.  The purpose of end-to-end congestion management is to ensure that congestion is controlled from the sending device to the receiving device in a dynamic fashion that can deal with changing bottlenecks.  The most common end-to-end congestion management tool is TCP Windows sizing.

TCP Window Sizing:

With window sizing TCP dynamically determines the number of frames to send at once without an acknowledgement.  It continuously ramps this number up dynamically if the pipe is empty and acknowledgements are being received.  If a packet is dropped due to congestion and an acknowledgement is not received TCP halves the window size and starts the process over.  This provides a mechanism in which the maximum available throughput can be achieved dynamically.

Below is a diagram showing the dynamic window size (total packets sent prior to acknowledgement) over the course of several round trips.  You can see the initial fast ramp up followed by a gradual increase until a packet is lost, from there the window is reduced and the slow ramp begins again.

image If you prefer analogies I always refer to TCP sliding windows as a Keg Stand (http://en.wikipedia.org/wiki/Keg_stand.)

File:Kegstand147.jpg

In the photo we see several gentleman surrounding a keg, with one upside down performing a keg stand.

To perform a keg stand:

  • Place both hands on top of the keg
  • 1-2 Friend(s) lift your feet over your head while you support your body weight on locked-out arms
  • Another friend places the keg’s nozzle in your mouth and turns it on
  • You swallow beer full speed for as long as you can

What the hell does this have to do with TCP Flow Control? I’m so glad you asked.

During a keg stand your friend is trying to push as much beer down your throat as it can handle, much like TCP increasing the window size to fill the end-to-end pipe.  Both of your hands are occupied holding your own weight, and your mouth has a beer hose in it, so like TCP you have no native congestion signaling mechanism.  Just like TCP the flow doesn’t slow until packets/beer drops, when you start to spill they stop the flow.

So that’s an example of end-to-end congestion management.  Within Ethernet and FCoE specifically we don’t have any native end-to-end congestion tools (remember TCP is up on L4 and we’re hanging out with the cool kids at L2.)  No problem though because We’re talking FCoE right?  FCoE is just a L1-L2 replacement for Fibre Channel (FC) L0-L1, so we’ll just use FC end-to-end congestion management… Not so fast boys and girls, FC does not have a standard for end-to-end congestion management, that’s right our beautiful over engineered lossless FC has no mechanism for handling network wide, end-to-end congestion.  That’s because it doesn’t need it.

FC is moving SCSI data, and SCSI is sensitive to dropped frames, latency is important but lossless delivery is more important.  To ensure a frame is never dropped FC uses a hop-by-hop flow control known as buffer-to-buffer (B2B) credits. At a high level each FC device knows the amount of buffer spaces available on the next hop device based on the agreed upon frame size (typically 2148 bytes.)  This means that a device will never send a frame to a next hop device that cannot handle the frame.  Let’s go back to the world of analogy.

Buffer-to-buffer credits:

The B2B credit system works in the same method you’d have 10 Marines offload and stack a truckload of boxes (‘fork-lift, we don’t need no stinking forklift.’)  The best system to utilize 10 Marines to offload boxes is to line them up end-to-end one in the truck and one on the other end to stack.  Marine 1 in the truck initiates the send by grabbing a box and passing it to Marine 2, the box moves down the line until it gets to the target Marine 10 who stacks it.  Before any Marine hands another Marine a box they look to ensure that Marines hands are empty verifying they can handle the box and it won’t be dropped.  Boxes move down the line until they are all offloaded and stacked.  If anyone slows down or gets backed up each marine will hold their box until the congestion is relieved.

In this analogy the Marine in the truck is the initiator/server and the Marine doing the stacking is the target/storage with each Marine in between being a switch.

When two FC devices initiate a link they follow the Link-Initialization-Protocols (LIP.)  During this process they agree on an FC frame size and exchange the available dedicated frame buffer spaces for the link.  A sender is always keeping track of available buffers on the receiving side of the link.  The only real difference between this and my analogy is each device (Marine) is typically able to handle more than one frame (box) at once.

So if FC networks operate without end-to-end congestion management just fine why do we need to implement a new mechanism in FCoE, well there-in lies the rub.  Do we need QCN?  The answer is really Yes and No, and it will depend on design.  FCoE today provides the exact same flow control as FC using two standards defined within Data Center Bridging (DCB) these are Enhanced Transmission Selection (ETS) and Priority-Flow Control (PFC) for more info on theses see my DCB blog: http://www.definethecloud.net/?p=31.)  Basically ETS provides a bandwidth guarantee without limiting and PFC provides lossless delivery on an Ethernet network.

Why QCN:

The reason QCN was developed is the differences between the size, scale, and design of FC and Ethernet networks.  Ethernet networks are usually large mesh or partial mesh type designs with multiple switches.  FC designs fall into one of three major categories Collapsed core (single layer), Core edge (two layer) or in rare cases for very large networks edge-core-edge (three layer.)  This is because we typically have far fewer FC connected devices than we do Ethernet (not every device needs consolidated storage/backup access.)

If we were to design our FCoE networks where every current Ethernet device supported FCoE and FCoE frames flowed end-to-end QCN would be a benefit to ensure point congestion didn’t clog the entire network.  On the other hand if we maintain similar size and design for FCoE networks as we do FC networks, there is no need for QCN.

Let’s look at some diagrams to better explain this:

image

 image In the diagrams above we see a couple of typical network designs.  The Ethernet diagram shows Core at the top, aggregation in the middle, and edge on the bottom where servers would connect.  The Fibre Channel design shows a core at the top with an edge at the bottom.  Storage would attach to the core and servers would attach at the bottom.  In both diagrams I’ve also shown typical frame flow for each traffic type.  Within Ethernet, servers commonly communicate with one another as well network file systems, the WAN etc.  In an FC network the frame flow is much more simplistic, typically only initiator target (server to storage) communication occurs.  In this particular FC example there is little to no chance of a single frame flow causing a central network congestion point that could effect other flows which is where end-to-end congestion management comes into play.

What does QCN do:

QCN moves congestion from the network center to the edge to avoid centralized congestion on DCB networks.  Let’s take a look at a centralized congestion example (FC only for simplicity):

image In the above example two 2Gbbps hosts are sending full rate frame flows to two storage devices.  One of the storage devices is a 2Gbps device and can handle the full speed, the other is a 1Gbps device and is not able to handle the full speed. If these rates are sustained switch 3’s buffers will eventually fill and cause centralized congestion effecting frame flows to both switch 4, and 5.  This means that the full rate capable devices would be affected by the single slower device.  QCN is designed to detect this type of congestion and push it to the edge, therefore slowing the initiator on the bottom right avoiding overall network congestion.

This example is obviously not a good design and is only used to illustrate the concept.  In fact in a properly designed FC network with multiple paths between end-points central congestion is easily avoidable.

When moving to FCoE if the network is designed such that FCoE frames pass through the entire full-mesh network shown in the Common Ethernet design above, there would be greater chances of central congestion.  If the central switches were DCB capable but not FCoE Channel Forwarders (FCF) QCN could play a part in pushing that congestion to the edge.

If on the other hand you design FCoE in a similar fashion to current FC networks QCN will not be necessary.  An example of this would be:

imageThe above design incorporates FCoE into the existing LAN Core, Aggregation, Edge design without clogging the LAN core with unneeded FCoE traffic.  Each server is dual connected to the common Ethernet mesh, and redundantly connected to FCoE SAN A and B.  This design is extremely scalable and will provide more than enough ports for most FCoE implementations.

Summary:

QCN like other congestion management tools before it such as FECN and BECN have significant use cases.  As far as FCoE deployments go QCN is definitely not a requirement and depending on design will provide no benefit for FCoE.  It’s important to remember that the DCB standards are there to enhance Ethernet as a whole, not just for FCoE.  FCoE utilizes ETS and PFC for lossless frame delivery and bandwidth control, but the FCoE standard is a separate entity from DCB.

Also remember that FCoE is an excellent tool for virtualization which reduces physical server count.  This means that we will continue to require less and less FCoE ports overall especially as 40Gbps and 100Gbps are adopted.  Scaling FCoE networks further than today’s FC networks will most likely not be a requirement.

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Networking Showdown: UCS vs. HP Virtual Connect (Updated)

Note: I have made updates to reflect that Virtual Connect is two words, and technical changes to explain another method of network configuration within Virtual Connect that prevents the port blocking described below.  Many thanks to the Ken Henault at HP who graciously walked me through the corrections, and beat them into my head until I understood them.

I’m sitting on a flight from Honolulu to Chicago in route home after a trip to Hawaii for customer briefings.  I was hoping to be asleep at this point but a comment Ken Henault left on my ‘FlexFabric – Small Step, Right Direction’ post is keeping me awake… that’s actually a lie, I’m awake because I’m cramped into a coach seat for 8 hours while my fiancé, who joined me for a couple of days, enjoys the first class luxuries of my auto upgrade, all the comfort in the world wouldn’t make up for the looks I got when we landed if I was the one up front.

So, being that I’m awake anyway I thought I’d address the comment from the aforementioned post.  Before I begin I want to clarify that my last post had nothing to do with UCS, I intentionally left UCS out because it was designed with FCoE in mind from the start so it has native advantages in an FCoE environment.  Additionally within UCS you can’t get away from FCoE, if you want Fibre Channel connectivity your using FCoE so it’s not a choice to be made (iSCSI, NFS, and others are supported but to connect to FC devices or storage it’s FCoE.) The blog was intended to state exactly what it did: HP has made a real step into FCoE with FlexFabric but there is still a long way to go. To see the original post click the link (http://www.definethecloud.net/?p=419.)

I’ve got a great deal of respect for both Ken and HP whom he works for.  Ken knows his stuff, our views may differ occasionally but he definitely gets the technology.  The fact that Ken knows HP blades inside, outside, backwards forwards and has a strong grasp on Cisco’s UCS made his comment even more intriguing to me, because it highlights weak spots in the overall understanding of both UCS and server architecture/design as it pertains to network connectivity. 

Scope:

This post will cover the networking comparison of HP C-Class using Virtual Connect (VC) modules and Virtual Connect (VC) management as it compares to the Cisco UCS Blade System.  This comparison is the closest ‘apples-to-apples’ comparison that can be done between Cisco UCS and HP C-Class.  Additionally I will be comparing the max blades in a single HP VC domain which is 64 (4 chassis x 16 blades) against 64 UCS blades which would require 8 Chassis.

Accuracy and Objectivity:

It is not my intent to use numbers favorable to one vendor or the other.  I will be as technically accurate as possible throughout, I welcome all feedback, comments and corrections from both sides of the house.

HP Virtual Connect:

VC is an advanced management system for HP C-Class blades that allows 4 blade chassis to be interconnected and managed/networked as a single system.  In order to provide this functionality the LAN/SAN switch modules used must be VC and the chassis must be interconnected by what HP calls a stacking-link.  HP does not consider VC Ethernet modules to be switches, but for the purpose of this discussion they will be.  I make this decision based on the fact that: They make switching decisions and they are the same hardware as the ProCurve line of blade switches.

Note: this is a networking discussion so while VC has other features they are not discussed here.

Let’s take a graphical view of a 4-chassis VC domain.

image In the above diagram we see a single VC domain cabled for LAN and SAN connectivity.  You can see that each chassis is independently connected to SAN A and B for Fibre Channel access, but Ethernet traffic can traverse the stacking-links along with the domain management traffic.  This allows a reduced number of uplinks to be used from the VC domain to the network for each 4 chassis VC domain.  This solution utilizes 13 total links to provide 16 Gbps of FC per chassis (assuming 8GB uplinks) and 20 Gbps of Ethernet for the entire VC domain (with blocking considerations discussed below.)  More links could be added to provide additional bandwidth.

This method of management and port reduction does not come without its drawbacks.  In the next graphic I add loop prevention and server to server communication.

image

The first thing to note in the above diagram is the blocked link.  When only a single vNet is configured accross the VC Domain (1-4 chassis) only 1 link or link aggregate group may forward per VLAN.  This means that per VC domain there is only one ingress or egress point to the network per VLAN.  This is because VC is not ‘stacking’ 4 switches into one distributed switch control plane but instead ‘daisy-chaining’ four independent switches together using an internal loop prevention mechanism.  This means that to prevent loops from being caused within the VC domain only one link can be actively used for upstream connectivity per VLAN.

Because of this loop prevention system you will see multiple-hops for frames destined between servers in separate chassis, as well as frames destined upstream in the network.  In the diagram I show a worst case scenario for educational purposes where a frame from a server in the lower chassis must hop three times before leaving the VC domain.  Proper design and consideration would reduce these hops to two max per VC domain.

**Update**

This is only one of the methods available for configuring vNets within a VC domain.  The second method will allow both uplinks to be configured using separate vNets which allows each uplink to be utilized even within the same VLANs but segregates that VLAN internally.  The following diagram shows this configuration.

image

In this configuration server NIC pairs will be configured to each use one vNet and NIC teaming software will provide failover.  Even though both vNets use the same VLAN the networks remain separate internally which prevents looping, upstream MAC address instability etc.  For example a server utilizing only two onboard NICs would have one NIC in vNet1 and one in vNet2.  In the event of an uplink failure for vNet1 the NIC in that vNet would have no north/south access but NIC teaming software could be relied upon to force traffic to the NIC in vNet 2. 

While both methods have advantages and disadvantages this will typically be the preferred method to avoid link blocking and allow better bandwidth utilization.  In this configuration the center two chassis will still require an extra one or two hops to send/receive north/south traffic depending on which vNet is being used.

**End Update**

The last thing to note is that any Ethernet cable reduction will also result in lower available bandwidth for upstream/northbound traffic to the network.  For instance in the top example above only one link will be usable per VLAN.  Assuming 10GE links, that leaves 10G bandwidth upstream for 64 servers.  Whether that is acceptable or not depends on the particular I/O profile of the applications.  Additional links may need to be added to provide adequate upstream bandwidth.  That brings us to our next point:

Calculating bandwidth needs:

Before making a decision on bandwidth requirements it is important to note the actual characteristics of your applications.  Some key metrics to help in design are:

  • Peak Bandwidth
  • Average Bandwidth
  • East/West traffic
  • North/South Traffic

For instance, using the example above, if all of my server traffic is East/West within a single chassis then the upstream link constraints mentioned are mute points.  If the traffic must traverse multiple chassis the stacking-link must be considered.  Lastly if traffic must also move between chassis as well as North/South to the network, uplink bandwidth becomes critical.  With networks it is common to under-architect and over-engineer, meaning spend less time designing and throw more bandwidth at the problem, this does not provide the best results at the right cost.

Cisco Unified Computing System:

Cisco UCS takes a different approach to providing I/O to the blade chassis.  Rather than placing managed switches in the chassis UCS uses a device called an I/O Module or Fabric Extender (IOM/FEX) which does not make switching decisions and instead passes traffic based on an internal pinning mechanism.  All switching is handled by the upstream Fabric Interconnects (UCS 6120 or 6140.)  Some will say the UCS Fabric Interconnect is ‘not-a-switch’ using the same logic as I did above for HP VC devices the Fabric Interconnect is definitely a switch.  In both operational modes the interconnect will make forwarding decisions based on MAC address.

One major architectural difference between UCS and HP, Dell, IBM, Sun blade implementations is that the switching and management components are stripped from the individual chassis and handled in the middle of row by a redundant pair of devices (fabric interconnects.)  These devices replace the LAN Access and SAN edge ports that other vendors Blade devices connect to.  Another architectural difference is that the UCS system never blocks server links to prevent loops (all links are active from the chassis to the interconnects) and in the default mode, End Host mode it will not block any upstream links to the network core.  For more detail on these features see my posts: Why UCS is my ‘A-Game Server Architecture http://www.definethecloud.net/?p=301, and UCS Server Failover http://www.definethecloud.net/?p=359.) 

A single UCS implementation can scale to  a max 40 Chassis 320 servers using a minimal bandwidth configuration, or 10 chassis 80 servers using max bandwidth depending on requirements.  There is also flexibility to mix and match bandwidth needs between chassis etc.  Current firmware limits a single implementation to 12 chassis (96 servers) for support and this increases with each major release.  Let’s take a look at the 8 chassis 64 server implementation for comparison to an equal HP VC domain.

image

In the diagram above we see an 8 chassis 64 server implementation utilizing the minimum number of links per chassis to provide redundancy (the same as was done in the HP example above.  Here we utilize 16 links for 8 chassis providing 20Gbps of LAN and SAN traffic to each chassis.  Because there is no blocking required for loop-prevention all links shown are active.  Additionally because the Fabric Interconnects shown here in green are the access/edge switches for this topology all east/west traffic between servers in a single chassis or across chassis is fully accounted for.  Depending on bandwidth requirements additional uplinks could be added to each chassis.  Lastly there would be no additional management cables required from the interconnects to the chassis as all management is handled on dedicated, prioritized internal VLANs.

In the system above all traffic is aggregated upstream via the two fabric interconnects, this means that accounting for North/South traffic is handled by calculating the bandwidth needs of the entire system and designing the appropriate number of links.

Side by Side Comparison:

imageIn the diagram we see a maximum server scale VC Domain compared to an 8 chassis UCS domain.  The diagram shows both domains connected up to a shared two-tier SAN design (core/edge) and 3 tier network design (Access, Aggregation, Core.)  In the UCS domain all access layer connectivity is handled within the system.

In the next diagram we look at an alternative connectivity method for the HP VC domain utilizing the switch modules in the HP chassis as the access layer to reduce infrastructure.

image

In this method we have reduced the switching infrastructure by utilizing the onboard switching of the HP chassis as the access layer.  The issue here will be the bandwidth requirements and port costs at the LAN aggregation/SAN core.  Depending on application bandwidth requirements additional aggregation/core ports will be required which can be more costly/complex than access connectivity.  Additionally this will increase cabling length requirements in order to tie back to the data center aggregation/core layer. 

Summary:

When comparing UCS to HP blade implementations a base UCS blade implementation is best compared against a single VC domain in order to obtain comparable feature parity.  The total port and bandwidth counts from the chassis for a minimum redundant system are:

  HP Cisco
Total uplinks 13 16
Gbps FC 16 per chassis N/A
Gbps Ethernet 10 per VLAN per VC Domain/ 20 Total N/A
Consolidated I/O N/A 20 per chassis
Total Chassis I/O 21 Gbps for 16 servers 20 Gbps for 8 servers

 

This does not take into account the additional management ports required for the VC domain that will not be required by the UCS implementation.  An additional consideration will be scaling beyond 64 servers.  With this minimal consideration the Cisco UCS will scale to 40 chassis 320 servers where the HP system scales in blocks of 4 chassis as independent VC domains.  While multiple VC domains can be managed by a Virtual Connect Enterprise Manager (VCEM) server the network stacking is done per 4 chassis domain requiring North/South traffic for domain to domain communication.

The other networking consideration in this comparison is that in the default mode all links shown for the UCS implementation will be active.  The HP implementation will have one available uplink or port aggregate uplink per VLAN for each VC domain, further restraining bandwidth and/or requiring additional ports.

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FlexFabric – Small Step, Right Direction

Note: I’ve added a couple of corrections below thanks to Stuart Miniman at Wikibon (http://wikibon.org/wiki/v/FCoE_Standards)  See the comments for more.

I’ve been digging a little more into the HP FlexFabric announcements in order to wrap my head around the benefits and positioning.  I’m a big endorser of a single network for all applications, LAN, SAN, IPT, HPC, etc. and FCoE is my tool of choice for that right now.  While I don’t see FCoE as the end goal, mainly due to limitations on any network use of SCSI which is the heart of FC, FCoE and iSCSI, I do see FCoE as the way to go for convergence today.  FCoE provides a seamless migration path for customers with an investment in Fibre Channel infrastructure and runs alongside other current converged models such as iSCSI, NFS, HTTP, you name it.  As such any vendor support for FCoE devices is a step in the right direction and provides options to customers looking to reduce infrastructure and cost.

FCoE is quickly moving beyond the access layer where it has been available for two years now.  That being said the access layer (server connections) is where it provides the strongest benefits for infrastructure consolidation, cabling reduction, and reduced power/cooling.  A properly designed FCoE architecture provides a large reduction in overall components required for server I/O.  Let’s take a look at a very simple example using standalone servers (rack mount or tower.)

imageIn the diagram we see traditional Top-of-Rack (ToR) cabling on the left vs. FCoE ToR cabling on the right.  This is for the access layer connections only.  The infrastructure and cabling reduction is immediately apparent for server connectivity.  4 switches, 4 cables, 2-4 I/O cards reduced to 2, 2, and 2.  This is assuming only 2 networking ports are being used which is not the case in many environments including virtualized servers.  For servers connected using multiple 1GE ports the savings is even greater.

Two major vendor options exist for this type of cabling today:

Brocade:

  • Brocade 8000 – This is a 1RU ToR CEE/FCoE switch with 24x 10GE fixed ports and 8x 1/2/4/8G fixed FC ports.  Supports directly connected FCoE servers. 
    • This can be purchased as an HP OEM product.
  • Brocade FCoE 10-24 Blade – This is a blade for the Brocade DCX Fibre Channel chassis with 24x 10GE ports supporting CEE/FCoE.  Supports directly connected FCoE servers.

Note: Both Brocade data sheets list support for CEE which is a proprietary pre-standard implementation of DCB which is in the process of being standardized with some parts ratified by the IEEE and some pending.  The terms do get used interchangeably so whether this is a typo or an actual implementation will be something to discuss with your Brocade account team during the design phase.  Additionally Brocade specifically states use for Tier 3 and ‘some Tier 2’ applications which suggests a lack of confidence in the protocol and may suggest a lack of commitment to support and future products.  (This is what I would read from it based on the data sheets and Brocade’s overall positioning on FCoE from the start.)

Cisco:

  • Nexus 5000 – There are two versions of the Nexus 5000:
    • 1RU 5010 with 20 10GE ports and 1 expansion module slot which can be used to add (6x 1/2/4/8G FC, 6x 10GE, 8x 1/2/4G FC, or 4x 1/2/4G FC and 4x 10GE)
    • 2RU 5020 with 40 10GE ports and 2 expansion module slots which can be used to add (6x 1/2/4/8G FC, 6x 10GE, 8x 1/2/4G FC, or 4x 1/2/4G FC and 4x 10GE)
    • Both can be purchased as HP OEM products.
  • Nexus 7000 – There are two versions of the Nexus 7000 which are both core/aggregation Layer data center switches.  The latest announced 32 x 1/10GE line card supports the DCB standards.  Along with support for Cisco Fabric path based on pre-ratified TRILL standard.

Note: The Nexus 7000 currently only supports the DCB standard, not FCoE.  FCoE support is planned for Q3CY10 and will allow for multi-hop consolidated fabrics.

Taking the noted considerations into account any of the above options will provide the infrastructure reduction shown in the diagram above for stand alone server solutions.

When we move into blade servers the options are different.  This is because Blade Chassis have built in I/O components which are typically switches.  Let’s look at the options for IBM and Dell then take a look at what HP and FlexFabric bring to the table for HP C-Class systems.

IBM:

  • BNT Virtual Fabric 10G Switch Module – This module provides 1/10GE connectivity and will support FCoE within the chassis when paired with the Qlogic switch discussed below.
  • Qlogic Virtual Fabric Extension Module – This module provides 6x 8GB FC ports and when paired with the BNT switch above will provide FCoE connectivity to CNA cards in the blades.
  • Cisco Nexus 4000 – This module is an DCB switch providing FCoE frame delivery while enforcing DCB standards for proper FCoE handling.  This device will need to be connected to an upstream Nexus 5000 for Fibre Channel Forwarder functionality.  Using the Nexus 5000 in conjunction with one or more Nexus 4000s provides multi-hop FCoE for blade server deployments.
  • IBM 10GE Pass-Through – This acts as a 1-to-1 pass-through for 10GE connectivity to IBM blades.  Rather than providing switching functionality this device provides a single 10GE direct link for each blade.  Using this device IBM blades can be connected via FCoE to any of the same solutions mentioned under standalone servers.

Note: Versions of the Nexus 4000 also exist for HP and Dell blades but have not been certified by the vendors, currently only IBM supports the device.  Additionally the Nexus 4000 is a standards compliant DCB switch without FCF capabilities, this means that it provides the lossless delivery and bandwidth management required for FCoE frames along with FIP snooping for FC security on Ethernet networks, but does not handle functions such as encapsulation and de-encapsulation.  This means that the Nexus 4000 can be used with any vendor FCoE forwarder (Nexus or Brocade currently) pending joint support from both companies.

Dell

  • Dell 10GE Pass-Through – Like the IBM pass-through the Dell pass-through will allow connectivity from a blade to any of the rack mount solutions listed above.

Both Dell and IBM offer Pass-Through technology which will allow blades to be directly connected as a rack mount server would.  IBM additionally offers two other options: using the Qlogic and BNT switches to provide FCoE capability to blades, and using the Nexus 4000 to provide FCoE to blades. 

Let’s take a look at the HP options for FCoE capability and how they fit into the blade ecosystem.

HP:

  • 10GE Pass-Through – HP also offers a 10GE pass-through providing the same functionality as both IBM and Dell.
  • HP FlexFabric – The FlexFabric switch is a Qlogic FCoE switch OEM’d by HP which provides a configurable combination of FC and 10GE ports upstream and FCoE connectivity across the chassis mid-plane.  This solution only requires two switches for redundancy as opposed to four with FC and Ethernet configurations.  Additionally this solution works with HP FlexConnect providing 4 logical server ports for each physical 10GE link on a blade, and is part of the VirtualConnect solution which reduces the management overhead of traditional blade systems through  software.

On the surface FlexFabric sounds like the way to go with HP blades, and it very well may be, but let’s take a look at what it’s doing for our infrastructure/cable consolidation.

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With the FlexFabric solution FCoE exists only within the chassis and is split to native FC and Ethernet moving up to the Access or Aggregation layer switches.  This means that while reducing the number of required chassis switch components and blade I/O cards from four to two there has been no reduction in cabling.  Additionally HP has no announced roadmap for a multi-hop FCoE device and their current offerings for ToR multi-hop are OEM Cisco or Brocade switches.  Because the HP FlexFabric switch is a Qlogic switch this means any FC or FCoE implementation using FlexFabric connected to an existing SAN will be a mixed vendor SAN which can pose challenges with compatibility, feature/firmware disparity, and separate management models.

HP’s announcement to utilize the Emulex OneConnect adapter as the LAN on motherboard (LOM) adapter makes FlexFabric more attractive but the benefits of that LOM would also be recognized using the 10GE Pass-Through connected to a 3rd party FCoE switch, or a native Nexus 4000 in the chassis if HP were to approve and begin to OEM he product.

Summary:

As the title states FlexFabric is definitely a step in the right direction but it’s only a small one.  It definitely shows FCoE commitment which is fantastic and should reduce the FCoE FUD flinging.  The main limitation is the lack of cable reduction and the overall FCoE portfolio.  For customers using, or planning to use VirtualConnect to reduce the management overhead of the traditional blade architecture this is a great solution to reduce chassis infrastructure.  For other customers it would be prudent to seriously consider the benefits and drawbacks of the pass-through module connected to one of the HP OEM ToR FCoE switches.

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How Emulex Broke Out of the ‘Card Pusher’ Box

A few years back when my primary responsibility was architecting server, blade, SAN, and virtualization solutions for customers I selected the appropriate HBA based on the following rule: Whichever (Qlogic or Emulex) is less expensive today through the server OEM I’m using.  I had no technical or personal preference for one or the other.  They were both stable, performed, and allowed my customers to do what they needed to do.  On any given day one might show higher performance than another but that’s always subject to the testing criteria and will be fairly irrelevant for a great deal of customers.  At that point I considered them both ‘Card Pushers.’

Last year I had the opportunity to speak at two Emulex Partner product launch events in the UK and Germany.  My presentation was a vendor independent technical discussion on the drivers for consolidating disparate networks on 10GE and above.  I had no prior knowledge of the exact nature of the product being launched, and didn’t expect anything more than a Gen 2 single chip CNA, nothing to get excited over.  I was wrong.

Sitting through the Key Note presentations by Emulex executives I quickly realized OneConnect was something totally different, and with it Emulex was doing two things:

  1. Betting the farm on Ethernet
  2. Rebranding themselves as more than just a card pusher.

Now just to get this out of the way Emulex did not, has not, and to my knowledge will not stop pursuing better and faster FC technology, their 4GB and 8GB FC HBAs are still rock solid high performance pure FC cards.  What they were however doing is obviously placing a large bet (and R&D investment) on Ethernet as a whole.

OneConnect:

The Emulex OneConnect is a Generation 2 Converged Network Adapter (CNA), but it’s a lot more than that.  It also does TCP offload, operates as an iSCSI HBA, and handles FCoE including the full suite of DCB standards.  It’s the Baskin Robins of of I/O interface cards, although admittedly  no FCoTR support 😉 (http://www.definethecloud.net/?p=380)  The technology behind the card impressed me but the licensing model is what makes it matter.  With all that technology built into the hardware you’d expect a nice hefty price tag to go with it.  That’s not the case with the OneConnect card, the licensing options allow you to buy the card at a cost equivalent to competing 10GE NICs and license iSCSI or FCoE if/when desired (licensing models may vary with OEMs.)  This means Emulex, a Fibre Channel HBA vendor, is happy to sell you a high performance 10GE NIC.  In IT there is never one tool for every job, but as far as I/O cards go this one comes close.

You don’t have to take my word for it when it comes to how good this card is, HP’s decision to integrate it into blade and rack mount system boards speaks volumes.  Take a look at Thomas Jones post on the Emulex Federal Blog for more info (http://www.emulex.com/blogs/federal/2010/07/13/the-little-trophy-that-meant-a-lot/.)  Additionally Cisco is shipping OneConnect options for UCS blades and rack mounts, and IBM also OEMs the product.

In addition to the OneConnect launch Emulex has also driven to expand their market into other areas, products like OneCommand Vision promise to provide better network I/O monitoring and management tools, and are uniquely positioned to do this through the eyes of the OneConnect adapter which can see all networks connected to the server.

Summary:

Overall Emulex has truly moved outside of the ‘Card Pusher’ box and uniquely positioned themselves above their peers.  In an data center market where many traditional Fibre Channel vendors are clinging to pure FC like a sinking ship Emulex has embraced 10GE and offers a product that lets the customer choose the consolidation method or methods that work for them.

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FCoTR a Storage Revolution

As the industry has rapidly standardized and pushed adoption of Fibre Channel over Ethernet (FCoE) there continue to be many skeptics.  Many Fibre Channel gurus balk at the idea of Ethernet being capable of guaranteeing the right level of lossless delivery and performance required for the SCSI data their disks need.  IP Junkies like Greg Ferro (http://etherealmind.com/) balk at the idea of changing Ethernet in any way and insist that IP can solve all the worlds problems including world hunger (Sally Struthers over IP SSoIP.)  Additionally there is a fear from some storage professionals of having to learn Ethernet networks or being displaced by their Network counterparts.

In steps Fibre Channel over Token Ring (FCoTR.)  FCoTR promises to provide collisionless delivery using proven Token Ring networks.  FCoTR is proposed by industry recognized experts: E. Banks, K. Houston, S. Foskett, R. Plankers and W. C. Preston to solve the issues mentioned above and provide a network that can converge Fibre Channel onto Token Ring while maintaining the purity of IP and providing job protection to storage administrators.  FCoTR is synergistic network convergence for Data Center 3.0 and Cloud Computing.

FCoTR has taken the fast track into the public eye and will be interesting to watch as it evolves.  If IBM plays their card rights they may be able to ride this wave into displacing Cisco and regaining their dominance in that space.  For more information on FCoTR:

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