XFS with external disk for journal/metadata

Hi. I’m building a home server with a small SSD as the root disk and two very big HDDs for storage.

I decided to run all of these as JBOD (no RAID) and use regular rsync for redundancy. I thought this would be more straightforward to maintain and recover in case of a disk failure.

Anyway, I thought that the XFS filesystems created on the big HDDs make sense to have journal and or metadata written to some portion of the SSD to allow for greater performance.

But I have a few concerns.

  • in the examples I see, device is specified by /dev path. e.g. /dev/sda2. But this can easily change and I see no way to point at another device afterwards.
  • would data be recoverable from the volume in case of the external drive failure? Will it make any difference whether journal or metadata is offloaded?
  • what will give better boost of performance - metadata or journal offloading?

Any pointers appreciated!

P.S. or should I better use ext4 where I can just remove a missing/failed journal and recreate it?