Jump to content
Welcome to our new Citrix community!
  • 0

PVS on Azure - Blue Screen


Aran Walker1709161820

Question

I'm testing PVS on Azure and seeing a recurring issue where target's crash with the stop error "system thread exception not handled" in CvhdMp.sys. I'm using Server 2019 for a target OS, I've recreated everything from scratch multiple times now and get the same result. The target device has only the VDA and PVS Target software installed. I create the vDisk with no problem, and can boot from PVS in private mode just fine at first, multiple times even, and then start getting the Stop error, usually the next day. I've even left it powered off overnight...so boot and shutdown multiples time without issue, making no changes while it's running, and then leave it off overnight and the next day power on and get the BSOD. I thought maybe there was a windows update being pulled down while it was running, but I tried manually updating it and it still is fine, but then after a period of time won't boot.

 

I've currently using a D series v5 size in Azure, I'm going to test with a v3. Also going to try Win 2022 to see if that does the same thing. but figured I'd post this and see if anyone else had seen this.

 

Thanks!

Link to comment

9 answers to this question

Recommended Posts

  • 0

Can you check if you have Accelerated Networking enabled in your provisioned VM that crashes? We don't currently support this for target VMs (but it should be used in the PVS Server) for this very reason -- each time a VM is started by Azure, it can end up on a different host with different Accelerated Networking hardware and sometimes this leads to problems. We expect to fix this in an upcoming release, but for the moment accelerated networking is not supported in targets.


Simon

Link to comment
  • 0

Hi Simon, 

Thanks for the feedback! Yes, I did try that, I don't think it was mentioned in the production documentation but I found a blog from back in October during the preview period that mentioned it not being supported so I went back and rebuilt my master VM from scratch with no accelerated network and made sure it was off on all my target VM's but it still crashed. I do have it enabled for the PVS Servers themselves. 

 

Yesterday I created another new master VM using the D2s v3 instead of the D2ds v5 that I had been using. So far it has not crashed, but when I started my v5 up this AM it didn't crash either, so I'm going to continue testing both and see what happens.

 

Thanks!

Link to comment
  • 0

Couple of things to note:

 

* Some of the newer machine sizes are enabling accelerated networking by default -- currently you need to ensure that it is disabled in the template VM you use when provisioning.D2s v5 is one of those.

* The crash is actually intermittent because it depends on the capability of the host that is chosen by Azure to run the VM when it is started - these hosts have a variety of different versions of the accelerated networking hardware and the crash will only happen in some cases. We have no control over this so we're working hard on supporting it in all cases - just not there yet.

 

Simon

Link to comment
  • 0

Hi Simon,

So a had created a new v5 last week with accelerated networking disabled from the very start, but I'm still getting blue screens. It was ok Friday and Sat but I booted it up this morning and got the crash, so I'm thinking there's still something Azure is changing in the background even without accelerated networking. The v3 I created last week has been stable so far.

 

A side note, re: the 2112 documentation, one other thing I ran into was under the "Manually creating target VMs on Azure" using BDM.exe to create the boot disk, step three says to choose the Msft partition and click Burn, but I couldn't find a VHD anywhere after that to upload. I eventually tried changing that dropdown to Citrix VHD File and then it saved a new VHD which I was able to upload to an Azure storage account and then created a Managed Disk from to boot my targets.

 

Thanks!

Link to comment
  • 0

Another day of testing with both v3 and v4 D series sizes (D2s v3 and D2ds v4) and not a single crash. I recall that faster networking was a new feature of the v5...and within the VM's both the v3 and v4 report 50Gbps whereas the v5 reports as 100Gbps. So my suspicion is that something in the v5 networking isn't compatible with PVS at this time, regardless of whether Accelerated Networking is enabled or not. At this point I'll probably just move forward with the v4's...

 

Thanks!

Link to comment
  • 0

Thanks for testing that! I dont have a lot of experience (as in none) with those v5 machine sizes but perhaps Azure is now forcing accelerated networking to be enabled or perhaps they are using newer hardware to implement it. We are working on being able to support accelerated networking in PVS target VMs on Azure but for the moment it is not supported.

 

Simon

Link to comment
  • 0

Hi Simon,

Yeah who knows what they are doing in the background...the option to disable Accelerated Networking is there and appears to work, and even reports it as "disabled" on the VM, but obviously there's some other factor at play with whatever the infrastructure is behind the faster networking. At this point since my v4's seem solid, I'm just going to move forward with my deployment and leave this alone. When this is resolved and Accelerated Networking is supported maybe I'll be able to re-size my VM's and take advantage of the performance improvements.

 

Thanks again for your input on this!

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...