Will the host be able to use unused resources of bhyve?

[rockybulwinkle]

I am setting up a TrueNAS Core 12 installation at work. I am running a few virtual machines (Alma Linux 8 guests) on it. Most of the time, their CPU is idling and they aren't using all of their RAM.

I don't intend to overcommit CPUs and RAM; currently I have 7/12 CPU cores and 30/96 GB of RAM allocated to various VMs. All the VMs are idling most of the time (they're serving things like gitlab, wikis, the company portal, etc), and, altogether, are only using about 7 GB. Are these unused resources available to the host system for purposes such as ZFS caching, NFS server processes, etc?

 

[NugentS]

I didn;t think that bhyve was that sophisticated

 

[rockybulwinkle]

Yeah, I'd be surprised if the RAM worked like that as it'd require some coordination between the guest and host. Doable I'm sure, but I doubt bhyve does it.

The CPUs on the other hand I would be a little surprised if it didn't support that, as I'd think bhyve processes would work like any other process and idle when they're not needed, freeing the resources to other processes. I have no idea if bhyve works like that though.

I'd still like some input from someone knowledgeable about the workings of bhyve.