If you're concerned about VDI storage capacity, you're doing something wrong!

One of the interesting conversations that came out of BriForum was around the storage capacity for VDI. Frequent readers know that when it comes to VDI storage, I focus on performance, rather than capacity.

One of the interesting conversations that came out of BriForum was around the storage capacity for VDI. Frequent readers know that when it comes to VDI storage, I focus on performance, rather than capacity. That said, I've also taken the position that VDI environments ought to mirror your traditional desktop environments, and so if your traditional desktop environments are based on persistent disk images then your VDI environment should be too.

I was talking to Kevin Goodman, CEO of FSLogix about this at BriForum. (Recall that FSLogix has an app hiding product where you can install all of your apps in your base image and then "hide" the apps that users shouldn't see or aren't licensed for. Gabe did a write-up on them last year.) Kevin and I were talking about how in the FSLogix world, you can do VDI on non-persistent disks while still getting all your apps into one image which you can use for every user and every department. (Since FSLogix isn't app virtualization then you don't have the compatibility limitations like with App-V or ThinApp.)

While we were talking about this, one of the BriForum attendees who was standing near by said something like, "Yeah, sounds good, but it will never work with us because we can't afford to use all that storage for each disk image."

Of course if you're using non-persistent disk images, then your cloning or mirroring or whatever VDI system will take care of managing just a single master image along with small delta images for each user. (That's nothing new.) But what was really interesting as we got into the conversation more was that this guy was holding off on VDI because he wanted to do persistent images, but his calculations for the needed disk space made the project too expensive.

That got me wondering—what storage is this guy using where persistent images actually take up all that physical space? We've had block-level deduplication for what, five years now? Even if you put your primary VDI storage as hard disks or SSDs in your VDI servers themselves, there are tons of software-based solutions that allow all your VMs to only store single instances of each unique block on the physical storage media.

Taking it a step further, I walked away from that conversation thinking, "Man, in today's world, if you're worried about the disk image size for your VDI project, you're doing something wrong!" I can't imagine building a new VDI environment based on storage that's so old it doesn't support that concept.

So I wonder . . . Am I alone in this? How do you view storage for VDI? While there are a million reasons to not do VDI, I can't possibly imagine someone saying, "Nah, I don't want to chew up all that expensive storage to give my users all their own disks." (Or "I don't want to waste the space to create 200GB images with every single enterprise app on there via FSLogix."


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The power of homebrew ZFS filesystem; with dedupe enabled; thin provisioned; utilizing SSD smartly; if it is properly designed can solve VDI storage performance and cost significantly.  Brian like you, I am also a fan of full clone persistent disk.  Nothing against link-clone I am sure they are great on certain use case.  I just like to keep my VDI simple.  With the help of mature ZFS dedupe storage technology, I mean why not..


I think when you have the likes of Atlantis Ilio in play, storage can no longer be used as the "excuse" to not adopt virtual desktops.

Hyper-V lovers could even used Fusion/PCI SSD cards and the new de-dupe feature in 2012R2 as an alternative but viable method (we did this in the last days of vWorkspace before Atlantis hooked us in :P).

Ultimately your not alone in this.


Yep, also a huge fan of dedup and full clones. Thinking of using VMware Mirage along with these - enabling you to use one tool for management of both physical and virtual machines.

Regarding FSLogix - I see two drawbacks:

- If you consider one toolset for both virtual and physical machines, ironically, storage on the local machines becomes and issue as the number of applications grows.

- Also talked to the FSlogix guys at Briforum London: I think the said they haven't seen a system with more than hundred applications - and would not recommend it. We're talking more like 400 applications here. Splitting this up in multiple images (with all necessary combinations) does not sound like a very good idea ...


@Michael, the upper limit is based upon available disk space, not the number of applications.

I would think what Brian has said about VDI-Storage would be true about ongoing physical desktop purchases. If you are not considering IOPs and storage for your physical PCs then you are doing it wrong.

Kevin Goodman



Kevin I don't get your last statement, when it comes to physical PC, IOPS has never been an issue..  On a certain server workload maybe but on traditional PC, there are not IO contention, they were fine running even with 7200RPM drives pre-VDI.  Obviously, if you want a little kick to it you would want an SSD.  But my point is there's no complex IOPS computation about how much spinning disk; 15000RPM or 10,000; SAS or SATA; and what kind of SSD.


We're actually dealing with this right now. Management has decided to buy SSD's to add to our existing Compellent infrastructure rather than "risk" something like Pure/Tegile/etc. So we're stuck with no dedupe, no compression, etc. So now we're trying to figure out how to do give 800 users a persistent experience with wildly different user requirements, while on a realistically finite amount of space. I did just read the article about Inifinio's new CTO so am checking them out now since we're definitely not going to be solving this with a hardware solution.



I was thinking about those Hybrid Drives when I wrote this. You know, the ones that use an algorithm to monitor data usage and place the most frequently used data into the SSD portion of the drive? Something like that should be a consideration for your next hardware refresh. It makes diskspace a non-issue for physical PCs/Laptops and would enable all of your applications to fit on the image.


Most companies waste too much resource by overlaying too many IO wasting background apps and management utilities.  Why would you use SCOM agents inside a VDI when you should leverage the hypervisor's tools for managing the health of your VDI infrastructure.

I can easily say that most companies and their management suites easily adds 20-30% tax to your VDI performance.  

Old ways in this new VDI world.


@Kyle What about when you have a "hybrid" model (real world) - physical and virtual desktops? Better to have the one management layer for all to act as the "glue" surely? - All about use cases at the end of the day.

RE: VDI health monitoring... hypervisor tools come with IO penalties of their own (no matter how small) but as this article implies storage is no longer a "real" concern anymore.