FreeNAS in VM guest on libvirt host with existing ZFS

[rasander]

Hi,

I have an existing libvirt/qemu setup, with ZFS as file system on the host. It runs nice and smooth

Now I want to install FreeNAS in a guest vm. For me, it does not feels like a good idea to double-ZFS it (running both ZFS on the host and inside the guest). Unfortunately it seems that I cannot get rid of ZFS partitions on the FreeNAS. I had hoped that I could create a single UFS partition, and let the host handle all the ZFS redundancy.

What is the suggested approach in my situation?

/Micki

 

[Ericloewe]

FreeNAS exclusively supports ZFS. No way around that.

 

[rasander]

I get that.

What is the suggested approach then, when having ZFS on both host and in the FreeNAS guest VM?

 

[Ericloewe]

Well, the "correct" way of running FreeNAS in a VM is to pass through an LSI SAS HBA so that FreeNAS and ZFS can operate on raw disks like they would on bare metal. This is the least painful option and you'd end up with two independent ZFS pools on two systems, one of which is backing FreeNAS' boot pool only.

You could give FreeNAS a virtual disk backed by a zvol from the host and use that, but that is a minefield of performance issues. Data integrity may also be iffy.