Since 2016, I’ve had a fileserver mostly just for backups. System is on 1 drive, RAID6 for files, and semi-annual cold backup.

I was playing with Photoprism, and their docs say “we recommend placing the storage folder on a local SSD drive for best performance.” In this case, the storage folder holds basically everything but the pictures themselves such as the database files.

Up until now, if I lost any database files, it was just a matter of rebuilding them by re-indexing my photos or whatever, but I’m looking for something more robust since I’ll have some friends/family using Pixelfed, Matrix, etc.

So my question is: Is it a valid strategy to keep database files on the SSD with some kind of nightly backup to RAID, or should I just store the whole lot on the RAID from the get go? Or does it even matter if all of these databases can fit in RAM anyway?

edit: I’m just now learning of ZFS caching which might be my answer.