Fusion 12 vm disk performance with MacOS 12.6 (Monterey)

[DTodd-]

Hello,

I'm running Fusion 12 on a 2018 MBP i9@2.9GHz,32GB,1TB Flash Drive with MacOS 12.6.

My issue is since upgrading to Fusion 12 and MacOS 12.6 the disk performance has become unusable when there is high IO needed.

I can run the same VM image on similar MBP running MacOS 10.14 and VMware Fusion 11.5 without issues.

The vm image is somewhat complicated, Win10 LTSC 2019 (basically Win10 Enterprise) with MS Deployment Tool (which builds Windows install images) and hyper-v (for creating the Windows WIM image). I have the hypervisor and IOMMU enabled in the Processor & Memory settings, disk type is NVMe and split into multiple files and disabled Side Channel Migrations in Advanced settings.

When large disk IO is needed, like deleting large files or the hyper-v begins building an image, the instance becomes almost unresponsive and in some cases require forced shutdown. However, this is not an issue with Fusion 11.5 and MacOS 10.14.

Are there additional settings or configurations options I should use?
How can I find the issue causing the performance loss?
Has anyone else experienced and resolved similar issues?

Thanks,

Dustin

[ColoradoMarmot]

What's the guest config?  On that machine, no more than 4 CPU (with nothing much running on the host).  

You can try disabling disk buffering (or turning it on if it's off).

Hyper-v is a major performance hit on later OS releases because of the switch to the apple hypervisor framework, and if that's the issue, you're out of luck.

[DTodd-]

The guest OS is somewhat small, 2 CPU, 8GB RAM, 120GB storage.

I'll look for the disk buffering option and give it a try.

Thanks

[DTodd-]

Sadly this seems to be a hypervisor issue with Fusion. In Parallels I can choose to use Parallel or Apple hypervisor.

https://kb.parallels.com/en/125195 

and when choosing the Parallels hypervisor my issue is resolved.

Does anybody know if the new tech preview 22h2 has the added feature to switch the hypervisor from Apple to VMware?

[ColoradoMarmot]

No, because in a future MacOS version (probably the one after Ventura), kernel extensions are going to be depreciated, so there will be no other option but to use the apple hypervisor framework.  VMWare made the decision to jump early to focus development on the long-term solution.