I'm planning on doing a tiny ZFS pool (once I've finally saved up for it - financials can be fun sometimes!), and was thinking of doing FreeBSD for ZFS and Linux for everything else on top of Xen.
I'm currently unsure how to make Linux see the ZFS pool though. I.... don't really like NFS. It's too glitchy in my experience. I use it to listen to music stored on a different machine from my laptop, which uses a long-range USB Wi-Fi adapter. If I unplug the adapter without cleanly unmounting /nfs, I get a kworker in an infinite loop. I googled around one afternoon and discovered that RHEL apparently found and fixed this in kernel 3.x. Interesting - I'm on Slackware, with kernel 4.1.x. >.<
I wish you could do cross-VM virtio. That would be awesome. Then I could export the device node corresponding to the whole pool from FreeBSD and just mount it as a gigantic ext4 filesystem on Linux. (Can you do that?!)
You could in theory have a zvol exported from a ZFS pool on FreeBSD to Linux via some remote block dev protocol. iSCSI comes to mind, as it would have to be cross platform. Then slap ext4 on top of that in Linux.
The idea feels "janky" though. Lots of overhead compared to just running ZFS on Linux.
Not just in theory. I've done this for a large dev/test Xen cluster (pool was actually on Solaris). Worked well. We made snapshots to match major release tags.
I'm currently unsure how to make Linux see the ZFS pool though. I.... don't really like NFS. It's too glitchy in my experience. I use it to listen to music stored on a different machine from my laptop, which uses a long-range USB Wi-Fi adapter. If I unplug the adapter without cleanly unmounting /nfs, I get a kworker in an infinite loop. I googled around one afternoon and discovered that RHEL apparently found and fixed this in kernel 3.x. Interesting - I'm on Slackware, with kernel 4.1.x. >.<
I wish you could do cross-VM virtio. That would be awesome. Then I could export the device node corresponding to the whole pool from FreeBSD and just mount it as a gigantic ext4 filesystem on Linux. (Can you do that?!)