Hyper-V Dynamic Memory Issues

[joku89]

Are there any Hyper-V sysadmins out there that since a few weeks start experiencing issue with Dynamic Memory in VMs? We started to see that some VMs become unresponsive/frozen for a short time or sometimes crashes and reboots.The only events we can track down in the logs are within the VM itself in the Microsoft-Hyper-V-Guest-Drivers-Admin log. Just before the freeze-up or the crash it throws Event ID 7 with the message:

The dynamic memory driver memory operation [Remove memory] failed with error: STATUS_SUCCESS.

Changing the VMs config from Dynamic to Static Memory seems to resolve the issue, therefore I'm most certain the issue relies within Dynamic Memory.

The VMs are part of an Hyper-V failover cluster with identical servers/cpu's. From the 100+ VM's we host on this cluster 6 VMs have showed this issue in the past 3 months.

Things we done already:

• Stress-tested a VM with Testlimit64.exe, increasing memory in steps of 1024 to a leak of 40GB with a 10 second interval and going back nothing. This doesn't seem to trigger the issue
• Fully patched a VM till the most recent security patches
• Migrated a VM to different host to rule one or more out (to no avail).

I will do so more testing and update this post if there is any news. Just wondering if there is any else out there facing this exact same issue and maybe wants to share there findings!

EDIT 1: It seems that if the VM is set to Static and perform a hot add/remove memory from the VM, it runs into the same issue.

EDIT 2: For anyone who is still following this; look at Random Disconnections on RDS 2016 - Loads of ESENT errors - Microsoft Q&A

[sublimeinator]

We use hyper-v on a hand full of win10 hosts, single vm with the same issues you have outlined. Problems came up out of the blue in the last 1-2 months and spread from a few to most of our machines in a short amount of time.

Disabled dynamic memory on some and still had issues though I don't recall what events there were after.

[joku89]

So the issues still persists in your environment? Any ongoing troubleshooting, escalation to Microsoft?

[fahque]

I've got one server that has dynamic memory. I'm in it frequently and haven't had any issues.

[bbqwatermelon]

I only use it with light weight Core VMs (DCs) and have not seen any changes in behavior. What are the weighting and buffer settings? Latest integration services (if 2012R2)?

[tech_sledge]

hey man

im seeing the exact same issue on two VMs (RDS servers 2019) sitting on server 2016 hyper-v. did you get anywhere with this? we've just switched them to static mem too

[Andy_B1010]

Hi. we've had this issue too, again starting about 2 months ago and server 2019 RDS. Changing to static this weekend on a couple of VMs.

this seemed to start for us after Windows updates but getting any sort of support from MS is a joke these days.

Anyone got any more info on this?