Disk pass through or ZFS datasets

[Keeper of the Keys]

A lot of guides suggest passing through physical disks to VMs when people want to run things like TrueNAS.

But what if you want to use your HDDs for more than just a NAS like for instance log devices to reduce "less important" writes to SSDs or PBS?

My gut says I should just setup the RAIDZ at the PVE level and pass whatever part of it I want through to the VM but I am wondering what your experience is.

Background:
I hope to soonish purchase a 4x3.5" sata bay + 2 nvme device on which I will be doing off-site backups by a family member using PBS so I have been considering different usage modes, at the moment I think I will be running PVE with virtualized PBS so that I could potentially run other VMs there too, for my main setup I also moved all (/most there are still logs I have not quashed yet) logging to a syslog server that runs with HDDs.

 

[Impact]

That's what I do. I have PVE manage the pool and give storage to a CT running SAMBA and that is then my NAS.

 

[DerekG]

But what if you want to use your HDDs for more than just a NAS like for instance log devices to reduce "less important" writes to SSDs or PBS

NAS system 'need' control of the complete disk. You therefore need to pass the drives (or better the controller) through to whatever NAS implementation you use, and then share the space to your servers/applications.

My gut says I should just setup the RAIDZ at the PVE level and pass whatever part of it I want through to the VM but I am wondering what your experience is.

That is the correct method, though I prefer TrueNAS running in a VM to running a zfs pool directly on Proxmox. It's far more flexible and easier to manage.

Background:
I hope to soonish purchase a 4x3.5" sata bay + 2 nvme device on which I will be doing off-site backups by a family member using PBS so I have been considering different usage modes, at the moment I think I will be running PVE with virtualized PBS so that I could potentially run other VMs there too, for my main setup I also moved all (/most there are still logs I have not quashed yet) logging to a syslog server that runs with HDDs.

Not a good idea, PBS is notorious for I/O ops, and you'll have a bad time trying to backup over a high latency WAN connection.
The ideal method is the maintain a local PBS backup and then have the remote PBS 'pull' the backup files from the local PBS.