I use mergerfs + snapraid on my HDDs for “cold” storage for the same reason: noise. Snapraid sync and scrub runs at 4am when I am not in the same room as the NAS.
The drives stay spun down 99% of the time, because I also use a ZFS mirrored pool on SSDs for “hot” files, although Btrfs could also work if you're opposed to ZFS because it's out of tree.
I also use mergerfs 'ff' (first found) create order, and put the SSDs first in the ordered fstab list of the mergerfs mount point. This gives me tiered storage: newly created files and reads hit the SSDs first. I use a mover script that runs nightly with the SnapRAID sync/scrub to keep space on the SSDs open.
The drives stay spun down 99% of the time, because I also use a ZFS mirrored pool on SSDs for “hot” files, although Btrfs could also work if you're opposed to ZFS because it's out of tree.
Basically using this idea, but with straight Debian instead of ProxMox: https://perfectmediaserver.com/05-advanced/combine-zfs-and-o...
I also use mergerfs 'ff' (first found) create order, and put the SSDs first in the ordered fstab list of the mergerfs mount point. This gives me tiered storage: newly created files and reads hit the SSDs first. I use a mover script that runs nightly with the SnapRAID sync/scrub to keep space on the SSDs open.
https://github.com/trapexit/mergerfs/blob/master/tools/merge...