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Jun 24 2013

Open letter to non-persistent VDI fanboys…

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An article that recently sparked my interest was authored by Harry Labana on Brian Madden’s blog entitled “Searching for a new way to enable non-persistent VDI. Can we leapfrog traditional PC management?”. I was suddenly taken back to early 2011, when I wrote an article entitled “Floating Pools are the way to go….”.

Labana, in his article, tries to find a better way to achieve non-persistent VDI for a broader user base that leapfrogs current physical desktop management practices.

I think it’s great that we have multiple and distinctive ways do to image and application management. However, in my opinion this is very 2011. The truth is that this whole image management thing has been leapfrogged by other technologies.

As times and technology have changed, I think it’s appropriate to revise the approach to the challenge of enabling non-persistent desktops. Following is my high level viewpoint on this challenge in the current environment.

 

Everything started with Full Clones – In the past everything was Full Clone. The more fortunate VDI early adopters were able to host desktops in enterprise SAN/NAS in the same way that many vSphere customers had been hosting server workloads. The SAN approach provided more performance and capacity than running VDI on direct attached storage. The setback with Full Clones is related to the cost of traditional storage architectures to deliver on capacity and performance required by VDI workloads.

Next came Linked Clones – Due to high storage cost adoption barrier the industry started looking at different ways to reduce capacity related storage costs and simplify image management. Linked Clones allowed organizations to define a single master image that would serve all virtual desktops along with delta individual files that grow overtime while storing guest OS write operations. After a defined period of time, which could be anything between hours or months, the desktop was refreshed to its pristine state recovering the storage capacity used by the delta files.

Because Linked Clones were supposed to be refreshed constantly, either resetting to its pristine state or replacing the base image, user profile management became even more critical for administrators implementing VDI.

At the same time the industry started talking about ways to maintain user-installed applications during these refresh operation cycles.

Then came Advanced Tiering – Clearly Linked Clones solved much of the capacity issue, but performance was still a high barrier adoption cost for VDI. The more performance was required the more disk spindles and storage cache was required, making traditional storage solutions very expensive.

With the rise of SSD and Flash technology came the Advanced Tiering. Advanced Tiering allowed administrators to provide a single small tier of SSD to support Linked Clone parent VMs, providing much improved performance with lower latency.

At that point in time, managing Linked Clones with non-persistent assignments and image management made a lot of sense. However, this is not 2011 anymore and things have drastically evolved allowing administrator to take different approaches.

Storage technologies have disentangled in the last couple years and now we have available, at very reasonable costs, a range of flash-based arrays, with data de-duplication, offline de-duplication and data compression. There are also in-memory solutions that offer similar benefits.

 

My claim in this article is that non-persistent desktops, Linked Clones and alternative image and app management solutions are not a requirement any longer for the large majority of use cases since now we can utilize fully provisioned persistent clones without the capacity and performance penalties.  Look at Pure Storage, XtremeIO and Atlantis.

In addition to the above, administrators can now use the same tools they are familiar with to manage Windows environment without incurring in additional learning and licensing costs, or instead of managing VDI in an entirely new and different way than physical devices.

If for any reason the use case translates into desktops being constantly refreshed, this can also be achieved while using fully provisioned clones. Additionally, despite what many think, fully provisioned desktops doesn’t translate into a full size desktop after it’s initiation. By default, all full clones are thin provisioned and will grow overtime, much like linked clones.

Now that we have the capacity and performance very well handled with Full Clones, why not utilize the same application delivery mechanisms you use for your physical desktops to deploy applications to users on their fully provisioned persistent desktops? Given that everything runs inside the datacenter, there are no networking constraints to get applications deployed in a quick a safe manner.

One of the only use-cases I can see for non-persistent desktops using layering or app virtualization is when the desktop must be destroyed after use and the applications for each individual varies in such a fashion that does not justify creating a master image containing those applications.

You have to ask yourself – why do you need to obliterate the user’s desktop after use? Perhaps you have a secure solution or a government standard you must follow.

 

In his article Labana address some of the key challenges with current technology options. I am offering my conclusions along with these key challenges.

  • Cost and performance of storage.
    • [My view] Storage technologies have evolved over the last couple years drastically cutting down costs associated to capacity and performance, effectively enabling organizations to deploy fully provisioned persistent desktops.
  • Management overhead of 200,000 local disks for users. (If this is used as an approach to address IOPS).
    • [My view] No need for direct-attached storage since newer storage technologies address the performance issues with Flash or RAM, and from a capacity perspective also leverages block de-duplication.
  • Compatibility of App-V with all apps and the packaging process costs.
    • [My view] Fully provisioned persistent clones do not require namespace or application virtualization solutions to deliver apps. Applications are deployed using traditional tools and storage de-duplication technologies take care or of capacity and growth issues.
  • Cost of replicating all 5000 apps globally when only 20 percent are common.
    • [My view] I am not entirely sure what that means, but all the applications will reside inside the datacenter, therefore no need to distribute applications to secondary datacenters and branch offices.
  • Building a scalable distribution infrastructure for layering solutions, while also expecting runtime provisioning of applications
    • [My view] No namespace or application virtualization required, removing management complexities and application compatibility issues.
  • Want to avoid UEM personalization and policy configuration complexity and do not want to build and manage a distributed SQL server infrastructure.
    • Sure, we don’t want that either.

 

I am not saying Labana is wrong, because I actually think he is dead right, for those cases where non-persistent desktops are used. My point is that in this new and modern world where all this amazing new storage technologies are helping us to simplify deployment and management there is no need to try to create complex science experiments to solve something that is already mastered and solved via a different disciplines; in this case storage.

I think it’s great that we now have such a range of technologies available to slice and dice VDI and Windows management, but ultimately I personally think they are not required for the large majority of use cases. For use cases where there is a fit, Unidesk, Horizon Mirage and other players on the market will be able to help you.

The only piece that is not addressed in any of the proposed solutions is Disaster Recovery. Certainly, being able to dynamically pull user applications or layers into a non-persistent image can be very useful in certain scenarios, especially when disaster recovering a datacenter into a remote location. For this end I would recommend looking at Horizon Mirage, enabling you to store de-duped copies of the desktops in a remote datacenter for easy restore, but there are other technologies that execute similar operations.

The idea that non-persistent desktops with layering and app delivery mechanisms reduce OpEx and CapEx costs of desktops can be an illusion. If you add license and training costs, not to mention complexity, you quickly realize that fully provisioned persistent desktops make sense. The only drawback with the majority of these new storage technologies is that it will only start making CapEx sense from a certain number users onwards. However, few of these vendors already started adding lease or rental-models that will fit the bill for most deployments.

Alternatively, for small deployments that may grow overtime hyper-converged scale-out solutions like Nutanix and VMware Distributed Storage can help to relieve performance bottlenecks making use of SSD for local caching. To my knowledge these solutions do not offer data de-duplication at this point in time, but they have a secondary magnetic disk tier for capacity.

Remember that I am discussing VDI pool deployment models along with application and image management, not storage technologies. It is unimportant to me the storage technology in use, as long as it is providing the capacity and performance required for the VDI workload.

 

Finally, I would like to address Harry Labana. I very much admire the work you have done for End User Computing, especially at Citrix and Appsense. I just happen to think we have a better and more simplistic ways to deliver VDI to end-users using technologies available to us today.

 

Disclaimer: Any views or opinions expressed in this article are my own, not my employer’s. The content published here is not read, reviewed, or approved by VMware and does not necessarily represent or reflect the views or opinions of VMware or any of its divisions, subsidiaries, or business partners.

This article was first published by Andre Leibovici (@andreleibovici) at myvirtualcloud.net.

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Permanent link to this article: http://myvirtualcloud.net/?p=5198

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  1. Rick Westrate

    Sure the technology enables you to deliver persistent full clone desktops in a cost-effective and performant manner…but it doesn’t solve a darn thing other than perpetuate the past labor intensive, highly fragile and inafective desktop mgmt practices of the past. Just virtualizing the desktop while managing it just like a physical simply moves your problems from the desktop to the Datacenter. You haven’t fundamentally solved anything.

    With today’s excellent options for application encapsulation, layering and persona management it IS possible to quite easily create an elegant non-persistent, (almost) empty image design that frees us of the sins of the past. Images get centrally managed and easily updated. Same for most apps. DR becomes extremely easy (just make the desktop dial tone available. As long as apps and persona are replicated you have instant availability.).

    So much can be achieved with a comprehensive stateless design and just because CAN now reasonably do full clones it doesn’t mean we SHOULD!

  2. Brian Madden (@brianmadden)

    There’s place for both in the world. As I wrote in “The VDI Delusion” last year and “The New VDI Reality” this year, for use cases where VDI makes sense, I am 100% on board with getting there as painlessly as possible, which in most cases is P2Ving (whether literally or figuratively) your existing desktop environment, and that’s going to require persistent support with one of these newer Atlantis/GreenBytes/Pure/Tegile, etc.

    But if you can also move to non-persistent and change the management of your desktops, then go for it! (Just recognize that that doesn’t have to be done at the same time as your move to VDI.)

    Either way is a “win” if VDI is really needed. One method doesn’t have to “win” versus another—it’s just up to whatever makes sense for that company at that time.

  3. TJ Vatsa (@TJVatsa)

    Lately, we have been seeing customers bring this issue up primarily from the perspective of desktop applications management and OPEX.

    1. Persistent desktop (aka full clones)
    a. PROS (Some of them)
    -Do not have the perennial issue of application management because there is no recompose involved.
    – Applications need not be reinstalled unless the desktop image itself needs to be replaced.
    – Consideration: VMware Mirage could come in very handy here.
    b. CONS
    – More provisioning time and potentially increased management overhead to manage each individually.
    – More storage capacity required. Inline de-dupe solution from some vendors will help here.
    – Consideration: VMware Mirage could help here though.
    2. But with non-persistent desktops (aka linked clones- floating or dedicated)
    a. PROS
    – Faster provisioning using the Composer.
    – Lesser storage capacity provided periodic recomposes are done.
    – Driven by business agility, linked clones will be provisioned much faster.
    b. CONS
    – Applications are nuked after recompose unless some third party desktop management tools like AppSense are used.
    – The feature & capabilities of these products vary drastically and these tools are “expensive”.
    Consideration: Could VMware Mirage be used in this scenario?

    Now with the newer storage vendors, promising performance and capacity, should one favor Option 1 or 2, depends on the use case that the customer is trying to address. It will also depend on the storage/storage-acceleration platform being used by the customer.

    IMO, it will land somewhere in between with a combination of Option 1 & 2.

    For instance, during one of my recent engagement, the % split of option 1 or 2 was driven by the use cases.
    1. 80% non-persistent desktops. Of these 60% floating and 40% dedicated assignments
    2. 20% persistent desktops for a specific use case involving field personnel. These were all dedicated assignments.

  4. Dale Carter

    While I understand where you are going with this I do not agree that non-persistent desktop are so 2011. In fact from what I am seeing in the field, customers are wanting help to get to the non-persistent, stateless desktop model due to the benefits this will bring them.

    As we move forward with VDI and deployments get larger the number 1 question I am seeing is how do we handle DR with VDI. Once customers get to that non-persistent stateless desktop DR becomes much easier than in a persistent model.

    For me right now the non-persistent model is still the way to go for most use cases that are moving to VDI, thats not to say that there is not a case for persistent desktops there is, its just the customers I am seeing want as much stateless desktops as possible.

    Also to ask a customer to move to a new Storage vendor or device as they start to deploy VDI could be a very tough sell indeed. Thats not to say its not the best option its just customers tend to not want to change to much all at once and would prefer to deploy VDI on hardware that they are already understand.

  5. Ravi

    Excellent article, we at Pure Storage call the linked clone era as VDI 1.0, easy for implementing the task users, lockdown desktops, … that’s done, (so 2011 as Andre says)

    In the VDI 2.0, you want to make your persistent desktop virtualization successful, one has to look into new ways of doing things. Amalgamation of technologies is great if you have PhD in slapping things together and a large amounts of mollah!

    From a storage perspective in the new world and the future, storage vendors are talking about –
    1. Deduplication aware, compression aware Primary storage
    2. 100% MLC (think cheap) flash based arrays, that fits right into your datacenters (FC or iSCSI)
    3. Affordable flash storage at the price of disk storage
    4. Not to mention super fast (lightening fast access) to user data
    5. Ability to scale to 1000s of users (due to 1,2,3,4)
    6. Last but not the least, easy manage-ability and hypervisor integrations (no PhD required)

    If you are still skeptical you can look at the reference architecture (http://www.vmware.com/files/pdf/partners/pure-storage/VMware-view-pure-storage-reference-architecture.pdf) that talks about a elegant design of 1000 desktops and how to scale, if the data reduction number don’t get you excited the record view planner score will get you which is same for both persistent and non-persistent desktops.

    With all the above advantages, if you are hosting a persistent desktops and don’t have to worry about the cost of storage (we are talking about < $100/desktop), and the IOPS/user response time why not do it on a all-flash storage array.

  6. xdguy

    Plenty of people talk about using Mirage to manage their persistent VDI solution (and I don’t just mean on this page) but are they overlooking it’s not actually supported or recommended? I believe the reason is Mirage hammers the living daylights out of your storage, even more so than fully persistent VDI does in the first place

    I was last told this as recently as a month ago by a VMware pre-sales tech.

    Ref – http://www.brianmadden.com/blogs/brianmadden/archive/2013/02/26/vmware-clarifies-my-quot-facts-quot-it-s-not-that-they-re-saying-not-to-use-mirage-with-view-they-re-just-saying-it-s-not-supported.aspx

  7. Andre Leibovici

    xdguy,

    You are correct that Mirage is not supported today with View, and this is due to CPU utilization; not storage. However, VMware is working to reduce resource consumption in order to fit VDI deployments properly.

    In saying that, the current solution does work well for backing up your VDI desktops to a remote site, of course, with the CPU consumption drawback.

    Andre

  8. Andre Leibovici

    Hi Rick,

    “With today’s excellent options for application encapsulation, layering and persona management it IS possible to quite easily create an elegant non-persistent, (almost) empty image design that frees us of the sins of the past. ”

    Sure, I don’t disagree with you. However, while you hire 3 engineers to work full time for a whole year to (hopefully) virtualize all 1,000 apps in your organization, with a single click I get all my users up-to-date since I am using the same solutions I use for physical desktops.

    It will make VDI much more palatable and digestible to CIO’s and IT Managers.

    Yes, DR is simpler with non-persistent desktops; and that’s why it comes down to use cases. If your case is application publishing only, perhaps TS would be more appropriate for your deployment. Now, if you need VDI, full-blown desktops, then fully provisioned persistent clones will be easier to manage, quicker to deploy, and easier and cheaper to maintain.

    Andre

  9. Randy J. Cress

    If VMware would have bought Ardence in 2006, you would be singing a different tune. For those of us that are using product instead of selling it, we know that VMware was a late comer in the client space for virtualization just as much as we know Citrix was a late player in the hypervisor space. You both have made decent acquisitions over the years but your still best at what you knew best to start. It is unfortunate for the customer that we must watch the big guys try and solve all of our woes so poorly. Luckily we have a disruption coming from the Android and IOS platforms that will hopefully end the madness of OS, application and data separation if Microsoft will take note.

    In the end with EMC being the parent company of VMware, it is in the best interest (not the best technology) for VMware to support and endorse solutions that consume more disk space and have requirements for higher IOPS.

  10. Andy

    Doesn’t Horizon View 5.2 take care of alot of these debates? The only real reason to run a dedicated pool (View 5.1 and prior) is to advertise thinapps to a specific machine so the users can do their job (talking licensed software that won’t be on the parent image). If you can thinapp software and advertise to a user name (Horizon App Manager) then there would be no need for a dedicated persistant view pool. (yes you could GPO a shortcut to the .exe with thinreg but most places I have been don’t maintain GPO’s very well and they are mess. Do we really want to add to the GPO mess?)

    A combination of floating desktops pools/roaming profiles with folder redirection/thin apps advertised via Horizon App Manager really bullet proofs a VDI rollout. The benefits of thinapps in conjunction with IOS/Android Mobile Apps is a game changer IMHO on how IT as a whole functions. I can grab a tablet and stream my thinapps on demand. No need to even stream a whole OS. Is Windows going to be obsolete in 10 years as everything will be SaaS?

    @TJVatsa… can you clarify what you mean in 2B “Applications are nuked after recompose ” Applications will still be advertised to dedicated machines after a recompose or refresh. If you Delete a dedicated machine then it will wipe the user entitlement and Assigned thinapps

  11. Tom

    Andre,

    You’re referenced a number of times how “new storage technologies” makes persistent desktops easier to manage. Can you give me specific examples of the technology you are referring to? Specifically the features you are referring to and the products that enable these features.

    I’m thinking what you’re referencing here might not be something every customer has or is willing to buy.

  12. Andre Leibovici

    Tom, I am referring to likes of Pure Storage, SimpliVity and XtremeIO that offer flash based performance and inline deduplication. Please note that you don’t have to go down this route if persistent desktops is not your specific use case.

    -Andre

  13. G. Simonson

    This resonates pretty well with the requirements for a next-gen VDI storage I am giving to our engineering team – we will be fine with any storage option as long as it is:
    – Fast (SSD-level fast or better)
    – Deduplicated (VDI is a very good use case for dedupe)
    – Cost-effective (to improve a business case against physical desktops)
    – Shared (to ensure resilience against host failures)

    All four are equally important, with, obviously, “cost-effective” stemming from “deduplicated”. Products like XtremIO or Pure Storage fit here quite nicely.

  14. Andre Leibovici

    I also recommend reading the article where I discuss why sometimes it’s better to utilize Linked Clones. http://myvirtualcloud.net/?p=5571

  15. Mark Sargent

    Anyone here used, tested or reviewed CloudVolumes? Viable product, game changer perhaps?

  16. Andre Leibovici

    @Mark there has been few articles and videos about CloudVolumes on BrianMadden.com. Harry Labana really likes it.

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