Posts Tagged Convergence

Key features for VDI storage

One of the biggest trends in IT infrastructure today is dedicated “storage systems” for VDI. I put “storage systems” in scare quotes because many of the vendors making these systems would object to being called a storage system. Regardless, the primary use case driving the sales of many of these systems is as a storage location for VDI. The reason for this is that traditional arrays have proven woefully inadequate to handle the amount and type of IO VDI can generate.

The architecture backing these systems varies greatly but when looking for a dedicated storage solution for your VDI environment, here are the top features I look for:

Speed. This one should be obvious but any storage system dedicated for VDI needs to be fast. Anyone who’s ever designed storage for a VDI environment can tell you that VDI workloads can generate tremendous amounts of most write-IO with very ‘bursty’ workload patterns. Traditional storage arrays with active-passive controllers, ALUA architecture and tiered HDD storage weren’t created with this workload in mind. Trying to design a VDI environment on this architecture can become (in some cases) cost and performance prohibitive. Indeed, many businesses are spending 40%-60% of their VDI budget on storage alone.

Today, the speed solution is being solved with a variety of methods. RAM is being used as a read/write location (e.g. Atlantis ILIO) for microsecond access times. “All flash” arrays are being purpose built to hold 100% SSD drives (Invicta, XtremIO, Pure, etc.). Adding to this, a whole host of “converged” compute/storage appliances are popping up utilizing local disk/flash for increased speed and simplicity (Nutanix, Simplivity, VSAN, ScaleIO, etc.) To reiterate, each of these systems I’ve mentioned can do more than just VDI, but VDI just happens to be a good use case for these solutions in many cases. If you’re looking for a place to put your VDI environment, the ability to rapidly process lots of random write IO should be of paramount concern and you should know that there are currently many ways this can be mitigated.

Data reduction. This one will be more controversial, particularly for non-persistent fanboys. Nevertheless, persistent VDI is a fact of life for many VDI environments. As such, large amounts of duplicate data will be written to storage and as a result, data reduction mechanisms become very important. De-duplication and compression will be the most effective methods and will be preferably in-line. Again, various solutions from Atlantis to Invicta, to XtremIO to Pure all offer these features but with very different architectures. If you have no persistent desktops then this feature becomes less important. However, data reduction can still be quite valuable in many non-persistent VDI architectures as well, as an example, XenDesktop MCS could greatly benefit from storage with de-duplication. I also find that many of my customers who start out thinking they’ll have only non-persistent desktops quickly discover during the course of their migration users who need persistence. Don’t be surprised by the need for this feature at a later point, plan for this at the beginning and make sure your storage platform has the appropriate data reduction features.

Scale. I don’t know how many VDI projects I’ve heard of where storage was purchased to support X amount of users only for the VDI project to take off faster and of larger scale than expected. The project then gets stalled because the storage system can’t handle more than the X amount of users it was designed for and the business doesn’t have enough budget to purchase another storage system. For this reason, any storage dedicated to VDI should be able to scale both “up” and “out”. “Up” to support more capacity and “out” to support more IO. The scaling of the system should be such that it is one unified system…not multiple systems with a unified control plane. The converged solutions are great at this, VSAN, Nutanix, et al. All flash arrays typically have this as well e.g. Invicta, XtremIO.

Ease of Management. This sounds basic and very obvious but make sure you evaluate “ease of management” when purchasing any VDI-specific storage solution. The reason for this is simple, any VDI-specific storage system is bound to have a much different architecture than any array’s you currently have in your environment. The harder it is to manage, the higher the learning curve will be for existing admins. My criteria for determining if a VDI storage system is “easy” to manage is this – “can my VDI admins manage this?” (and that’s no slight to VDI admins!). The management of the system shouldn’t require a lot of legacy SAN knowledge or skillsets. This makes the environment more agile by not having to rely on multiple teams for basic functions and doesn’t burden SAN teams with a disparate island of storage they must learn and manage. Again, many of the converged solutions are great at this as well as some of the newer AFA’s.

There are many other important factors in deciding what to look for in a storage solution for your VDI environment. Whatever the architecture, if it doesn’t include the above four features, I’d look elsewhere.

Note: Vijay Swami wrote an excellent article entitled “A buyer’s guide for the All Flash Array Market”. I found it interesting after I wrote this to read his thoughts and note how many of the things he looks for in an AFA are similar to my top features for VDI storage. Regardless, it’s good reading and if you haven’t already, check it out.

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End of year Randomness

I’m not big on “end of year” posts or predictions and lacking any other ideas, thought I’d write down some random thoughts about technology going through my head as this year draws to an end.

All Flash Array Dominance
I’m not buying the hype surrounding all flash array’s (AFA).  Certainly there are legitimate use cases and they’ll be deployed more in the near future than they have in the past but the coming dominance of all flash array’s, I think, has been greatly exaggerated.  It’s clear that the main problem these array’s are trying to solve is the extreme performance demands of some applications and I just think there are much better ways to solve this problem (e.g. local disk, convergence, local flash, RAM caching, etc) in most scenarios than purchasing disparate islands of SAN.  And many of the things that make an AFA so “cool” (e.g. in-line dedupe, compression, no RAID, etc.) would be even cooler if the technology could be incorporated into a hybrid array.  The AFA craze feels very much like the VDI craze to me, lots of hype about how “cool” the technology is but in reality a niche use case.  Ironically, VDI is the main AFA use case.

The Emergence of Convergence
This year has seen a real spike in interest and deployment of converged storage/compute software and hardware and I’m extremely excited for this technology going into 2014.  With VMware VSAN being GA in 2014, I expect that interest and deployment to rise to even greater heights.  VSAN has some distinct strategic advantages over other converged models that should really make the competition for this space interesting.  Name recognition alone is getting them a ton of interest.  Being integrated with ESXi gives them an existing install base that already dominates the data center.  In addition, it’s sheer simplicity and availability make it easy for anyone to try out.  Pricing still hasn’t been announced so that will be the big thing to watch for in 2014 with this offering, that and any new enhancements that come with general availability.  In addition to VSAN, EMC’s ScaleIO is another more ‘software-based’ rather than ‘appliance-based’ solution that is already GA that I’m looking forward to seeing more of in 2014.  Along with VMware and EMC, Nutanix, Simplivity, Dell, HP, VCE, et al. all have varying “converged” solutions as well so this isn’t going away any time soon.  With this new wave of convergence products and interest, expect all kinds of new tech buzzwords to develop!  I fully expect and predict “Software Defined Convergence” will become mainstream by the end of the year!

Random convergence links:
Duncan Epping VSAN article collection – http://www.yellow-bricks.com/virtual-san/
Scott Lowe – http://wikibon.org/wiki/v/VMware_VSAN_vs_the_Simplicity_of_Hyperconvergence
Cormac Hogan looks at ScaleIO – http://cormachogan.com/2013/12/05/a-closer-look-at-emc-scaleio/
Good look at VSAN and All-Flash Array performance – http://blogs.vmware.com/performance/2013/11/vdi-benchmarking-using-view-planner-on-vmware-virtual-san-part-3.html
Chris Whal musing over VSAN architecture – http://wahlnetwork.com/2013/10/31/muse-vmwares-virtual-san-architecture/?utm_source=buffer&utm_medium=twitter&utm_campaign=Buffer&utm_content=buffer59ec6

The Fall of XenServer
As any reader of this blog knows, I used to be a huge proponent of XenServer.  However, things have really gone downhill after 5.6 in terms of product reliability.  So much so that I really have a hard time recommending it at all anymore.  ESXi was always at the top of my list but XenServer remained a solid #2.  Now it’s a distant 3rd in my mind behind Hyper-V.  I’ll grant that there are many environments successfully and reliably running XenServer, I have built quite a few myself, but far too many suffer from bluescreen server crashes and general unreliability to be acceptable in many enterprises.  The product has even had to be pulled from the site to prevent people from downloading it while bugs were fixed.  I’ve never seen so many others express like sentiments about this product as I have seen this past year.

Random CTP frustration with XenServer:

Random stuff I’m reading
Colin Lynch has always had a great UCS blog and his two latest posts are great examples.  Best UCS blog out there, in my opinion:
UCS Manager 2.2 (El Capitan) Released
Under the Cisco UCS Kimono

I definitely agree with Andre here!  Too many customers don’t take advantage of CBRC and it’s so easy to enable:
Here is why your Horizon View deployment is not performing to it’s max!

Great collection of links and information on using HPs Moonshot ConvergedSystem 100 with XenDesktop by Dane Young:
Citrix XenDesktop 7.1 HDX 3D Pro on HP’s Moonshot ConvergedSystem 100 for Hosted Desktop Infrastructure (HDI)

In the end, this post ends up being an “end of year” post with a few predictions.  Alas, at least I got the “random” part right…

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Convergence and the Software-Defined Data Center

There’s been a lot of industry news lately regarding Software-Defined Storage, Software-Defined Data Centers and hyper-convergence .  After numerous conversations with various colleagues and friends about these concepts, I wanted to post my own thoughts on them and how I believe they are related.

First off, hyper-convergence has usually been used to denote the “next stage” in modern converged infrastructure.  With many of the popular reference architectures or pre-built systems representing some level of “convergence”, hyper-convergence has come to refer to those systems that combine multiple data center tiers into a single appliance. However, as a term, I’ve come to view “hyper-convergence” as a misnomer.  When looking at the modern landscape of integrated infrastructure platforms, there is only “convergence” and “simulated convergence”.  Examples of converged infrastructure include Nutanix, Simplivity, et al while simulated convergence examples can be found in vBlock, VSPEX and FlexPod.  And while there is differentiation within the simulated convergence platforms (e.g. pre-built vBlock vs. reference architectures VSPEX/FlexPod), they are only “converged” insofar as their disparate components are cabled and racked together in a branded rack and sometimes managed with common software (e.g. Cloupia).  With simulated convergence, each “tier” of the data center is still represented by separate hardware components and an attempt at unity is made through the use of “single-pane” management software.  Convergence differs from this in that data center tiers are consolidated into common hardware components which naturally increase management software simplicity as well.

Another interesting difference is that while simulated convergence offers simplified management and automation, convergence gives you Simulatedthese same things plus performance, cost and reduced complexity benefits as well.  Because convergence moves data center tiers into a common platform, this naturally puts the network/compute/storage into closer proximity to each other, enabling greater performance and reduced complexity.  Cost savings are achieved not only through hardware consolidation but operational expenditures can be lessened in a converged model as well.

None of this is to say that simulated convergence is worthless.  On the contrary, simulated convergence via management software and reference architecture/pre-built configurations can greatly increase the consume-ability and ease of management of these separate components.  Simulated convergence gives you increased efficiency on legacy platforms that organizations already have in place and already have knowledge on how to manage.  It’s an improvement over traditional processes but it is not actual convergence, which is the next logical progression.

Indeed, say what you will about specific converged offerings but it’s hard to see why convergence as a model wouldn’t be the clear path to simplified software-defined data centers.  No matter how much management software and automation you put in front of it, simulated convergence will always require specialized knowledge of various levels of divergent hardware components in order to properly maintain and run that model.  You would never deploy a vBlock and only train your support staff on just Cloupia or vCenter with VSI plugins.  No, for advanced troubleshooting and configuration an in-depth knowledge of all the network, hypervisor, compute, storage network and array components is necessary as well. Management software can mask the complexity, but it’s still there.  It doesn’t move the control plane, it just creates another one.

Converged infrastructure that relies on commodity hardware and is software/virtualization-based shifts the focus from tier-based component management and support to a more holistic data center view.  Under the converged model , the deployment and ongoing maintenance of the underlying infrastructure is greatly simplified, allowing for faster application deployment , monitoring and troubleshooting.  In short, you spend much less time on your physical infrastructure and more time focusing on the business.  Of course, hardware is still necessary on such a system but that’s not where the intelligence lies and as we’ve seen, there’s much less of it!

Going forward, I’m convinced that the popularity of convergence will only increase.  What will be interesting to see is how the major compute/storage vendors handle this shift.  As convergence increases, will a storage and compute vendor team up to sell their own converged solution?  Will one of the startup convergence companies be acquired?  Whatever happens, this will be one of the more exciting areas of IT to be involved with for many years to come.  I can’t wait!

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