[csydas]

HyperV has been overlooked by Microsoft for awhile in favor of Azure. You can get a basic HyperV host up and running pretty easily (even for free with the Core edition), but I would not call it great. My experience with HyperV is not a pleasant one as it struggles a lot and the error messages are often extremely cryptic. Similarly, there are some pretty outstanding bugs that existed for years that Microsoft didn't bother to fix -- for example, since HyperV 2019, there has been an impactful RCT bug† that can be triggered if you upgraded your HyperV hosts in a specific path (2016-2019) and any backup solution used HyperV's RCT. The result of the bug is extremely poor performance on any VM using RCT. Supposedly there was a patch last or this month that addressed it, but I've not heard any positive news from clients about this patch. Nevermind that Windows updates have frequently broken core HyperV functionality (as recent as December 2022 there were bugs where you couldn't start Virtual Machines or even create new ones due to bad Windows updates)

From my perspective, Microsoft doesn't want to deal with HyperV anymore, they want your machines up on Azure. I'd actively advise against HyperV simply because I don't see that Microsoft cares about on-premises.

† RCT == Changed Block Tracking for HyperV, basically faster backups by allowing the backup application to know exactly which blocks of the virtual disks have changed since the last backup and the backup application can do fast incrementals via this means.

[SahAssar]

Azure runs on a modified HyperV, right? Or are you saying they are using some other hypervisor there?

[csydas]

it does but i cannot tell why the azure performance is so different than on premises hyperv. i simply don’t know but the issues i’m describing here afaik did not affect azure instances. i do not know why but i thjnk it means there is a difference between on premises hyperv and azure hyperv or they do something to ensure the same issues don’t affect azure instances

but i simply don’t know why there is a difference

edit: if you search “hyperv rct bug” you will find forum posts fasts showing the timeline of this issue lasting years and many clients complaining that microsoft would not even acknowledge the issue publicly (or even in ms support cases) until very very recently