Laggy VMs

[steveg]

Wouldn't you be best running netsupport on it's own server, not on a DC? That's kind of the point of virtualising!

[mavhc]

Well, that's the point of containers anyway

[Gongalong]

Sorry guys, catching up here...

Do you have more vCPU cores assigned than there are physical cores in total? (And does that include hyperthreading fake cores?)

I'm guessing that the hosts just look at the logical processors available to them, even if hyperthreading? Not sure if it can be turned off on these servers, or if makes a great deal of difference.

 

Anyway, just a reminder that there are 32 logical processors available on each host. The way the VMs are divided up means that we have 29 VCPUs assigned on one host, and 30 on the other. Should I just bump up some of the VMs so they're at 32?

I meant total virtual ram assigned vs total physical ram in the physical server

For this, we have 68GB assigned on one host, and 50 on the other. A reminder that the servers have 192GB physical RAM each.

Wouldn't you be best running netsupport on it's own server, not on a DC? That's kind of the point of virtualising!

Having upped the memory the DC seems to cope. Might make upgrading a little easier, but it wasn't horrendous having just done it.

[mavhc]

So probably not overloaded.

 

Are all the VMs gen2, with the same drivers for network/disk/etc?

[Gongalong]

There are a mix of generations. Presumably I could update all the Gen 1s to 2 by just deleting, recreating, and attaching the disk?

[Gongalong]

I think I'm seeing this behaviour as well, but a little hard to tell because the CPU load is low. I'm checking with the consultant who built these as to whether we're safe to apply the fix detailed https://kevinholman.com/2019/07/22/windows-server-2019-hyper-v-might-only-use-half-the-available-cpus/

[Jaan]

There are a mix of generations. Presumably I could update all the Gen 1s to 2 by just deleting, recreating, and attaching the disk?

 

Think gen 2 are uefi and gen 1s aren't, so wouldn't boot if the disk are pre gen 2? (just thinking out loud here)

[mavhc]

There are a mix of generations. Presumably I could update all the Gen 1s to 2 by just deleting, recreating, and attaching the disk?

 

You can just upgrade to gen2 when they're off

[Gongalong]

Is there a particularly recommended method? Google is bring up a PowerShell script, among other mentions.

[mavhc]

I just do it from the hyper-v UI

[Gongalong]

Check these links out. The default scheduler has changed in Server 2019 Hyper-V and this may have an impact on any existing VM's that are not upgraded to the latest VM version:

https://kevinholman.com/2019/07/22/windows-server-2019-hyper-v-might-only-use-half-the-available-cpus/

https://www.altaro.com/hyper-v/hyper-v-core-scheduler/

https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/manage/manage-hyper-v-scheduler-types

Thanks @Smokebomb, we were definitely affected by this. There are teachers in so I can't update all servers, but have done most and the CPU usage is markedly better apportioned.