Personal vDisks – Part 2!

Howdy!  Welcome to Part 2 of my Citrix Personal vDisk blog.

Today’s blog will cover a more practical side of the Personal vDisk – use in a PVS streamed environment.  Well, it’s also true for a MCS environment too but I’m using PVS 🙂

As I mentioned in the last blog, you create the pools of Desktops with PvDs attached through Machine Catalogs.  In the case of MCS, you do this in Desktop Studio and you will notice TWO new catalog types.  Apologies for the misspelling of Catalogues but it’s a bug with Citrix – they’re American 🙂 

So, you can see there is Pooled with personal vDisk for MCS and Streamed with personal vDisk for PVS.  Now, the Streamed with personal vDisk is a bit misleading as you cannot actually create the pool here!  You have to do it through the XenDesktop Setup Wizard in PVS J.  You will need to be utilising the latest version of PVS, 6.1.

When you run through the XenDesktop Setup Wizard you will see a couple of different options; the first is that for machine type, you have the new option of Streamed with Personal vDisk (see below). 

XenDesktop Wizard 02

The next new option is when creating the Virtual Machines.  Notice that is has automatically picked up the local write cache disk (4 GB).  You can now decide on the size of the PvD for each user.  In the following video, Citrix elude to the fact that you can change the size of the PvD at a later date and that is it a relatively easy change – http://www.citrix.com/tv/#videos/5359 although according to the PvD FAQ http://support.citrix.com/article/CTX131553 “Expanding the vDisk is available through a PoSH script or by hypervisor console (resize of Personal vDisk)”. You can also select the drive letter if you wish to change it from the default. 

The next steps in the XenDesktop Setup Wizard are the same as in previous versions.  Once complete, you will have a pool of XenDesktops with a PvD attached! 

Now, before you can have users logging in and merrily filling up their PvD, you will need to do an additional step on your Streamed image, either in Private Mode or a Maintenance difference disk of the Standard mode image – so read and write mode basically.  Once the image is in Read/Write mode, log on, make any other changes you wish to make and then before shutting down you will need to run the Update Personal vDisk tool (from Start\Programs\Citrix).

This will then update the inventory which I believe collates a load of information about what is and isn’t going to be redirected to the PvD and other settings.  Handily, you get the option to shut down the VM once the inventory is updated.  This means you can include this step in your reseal script.

If however, you forgot and attempt to shutdown you will be reminded about this and prompted to run the Update Personal vDisk tool (see below).

WARNING! If you do not run this update before you shutdown and put the disk into Standard (Read) mode, you WILL NOT be able to use/see the Personal vDisk and get an error message when a user logs in. 

Now that you have created the Machine Catalog (assignments are created as in previous versions of XenDesktop), you have launched your PVS image in Read/Write mode and run the inventory update tool, shut down and put the PVS image into Standard mode, you are ready to get users logged on and using their brand new, shiny PvD!

When you launch a XenDesktop with PvD for the first time, it will assign that user to the VM so that every time that user logs in, they will always connect to the same VM.  This is because the PvD is attached at a Hypervisor level and not streamed so the user will only get their personalisation and applications by connecting to “their” VM.

So, that’s enough for Part 2 I think.  In Part 3, I’ll be diving deeper into the nuts and bolts of the PvD and how to configure various features and what my findings have been so stay tuned!

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4 thoughts on “Personal vDisks – Part 2!

  1. Hi Stephen,

    I have an issue in that when I run the Update Personal vDisk tool, auto-shut down the VM and then convert the primary vDisk back to standard, the next time users boot up to the new vDisk the workstation shuts down after about 60 seconds or so. Once that happens it can then be restarted and used as normal.

    If I log on quickly enough I see a dialog box with ‘Desktop update in progress’ (http://oi49.tinypic.com/67sk6s.jpg) so it appears to be a user-specific phase once the master image has been updated. It’s something of a pain because (a) it affects every single user,not just the first one and (b) it carries out a shutdown not a restart afterwards.

    Is this standard behaviour? Can I suppress it somehow?

    Cheers,
    Andy

  2. Hi Andy,

    Firstly, thanks for reading my blog. It’s good to know that it is being looked at. No, unfortunately, I haven’t seen this issue before. When I’ve run the Inventory Update, shutdown the vDisk and put it into Read-only mode, it’s worked for users logging in and assigned the VM to the user as expected. The only issue I’ve had is when I haven’t run the Inventory Update and received the error explained above.

    Unfortunately, I haven’t had time to publish my 3rd part in the PvD series I was writing where I explain about the Registry keys and values used for the PvD which allow you to control the weighting of the User vs. Application partitions, turning on and off user profile personalisation/integrating with UPM or AppSense etc. and some other settings including mount points (I must finish this and publish it). It may be worth looking here to see if there are any values that could control this second update. As far as I’m aware, this IS NOT standard behaviour. The Registry key is [HKLM\Software\Citrix\personal vDisk\Config].

    Having a quick lot, there are two Registry keys that may be working playing with:
    • BlockLogonIfUpdateInProgress
    • PowerOffAfterUpdate

    These are both DWORD values and in my environment, both of these are set to 0x00000001. Perhaps try changing them one at a time to 0x00000000 and see what happens? It could be that the disk is updating to associate that VM with that particular user but I haven’t seen this before. Changing the mentioned values may stop the shutdown?

    I will certainly try to replicate this issue in my lab and see if these values resolve it.

    My only other idea I can suggest at this time is how are you updating the vDisk? Are you using Private Mode to make the updates or Standard Mode with a Maintenance difference disk using the Versioning tool in PVS 6.1? It may be worth trying the other one to see if there is a difference, i.e. if you’re using Private Mode, put the vDisk into Standard Mode, create a new Maintenance difference disk and make the changes here and see what happens or vice versa. For more info on Versioning (if required) – http://tinyurl.com/c99f6z9.

    Thanks and keep me updated as it will be useful to know if you can resolve this as I’m sure we’ll come across it again at some stage. I will keep you informed if I’m able to reproduce the issue and resolve too.

    Cheers,

    Stephen

  3. Charles says:

    Stephen,

    Great Blog. I am also having the same issue of the VM’s shutting down after a version change is made. I will try the suggested reg key and see how it affects this behavior. One question that I did want to ask is if you have ever experienced any issues with having to reboot the VM’s multiple times after you bring the vDisk back into Standard mode ? My issue is after making changes and doing the update pvdisk, when the VM’s boot up they all shut down, but then I manually boot them up again and they stay up at that point. My problem usually comes the next day when users try to log in. We have to get into XenCenter or Studio and reboot each VM almost, because the users are saying their desktop does not come up. So, unless I manually reboot the VM’s after I make changes to the vDisk then I get this problem the next day.

    Have you ever had this problem ?

    • Hi Charles,

      No, I haven’t had this problem before but it will be worth having a lot at the registry settings that go with PvD to see if these make a difference. What version of PVS are you using? PVS 6.x? If so, do you use the versioning feature? The reason I ask is that if you are changing the disk image to Private and then back to Standard, it would be worth leaving the image in Standard Mode and creating a new Difference disk in Maintenance mode (Read/Write mode) and trying it this way. If you do have PVS 6.x and are unsure of the Versioning side to it, I have written a blog explaining this and how it works.

      Thanks,

      S

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