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.
Can you elaborate? (learning a lot at the moment).
My thought was to just copy over the whole database directory every night at like 2am. Though some of the services do offer built-in database backup tools which I assume are designed to do what you’re talking about.
Basically, you want to shut down the database before backing up. Otherwise, your backup might be mid-transaction, i.e. broken. If it’s docker you can just docker-compose down it, backup, and then docker-compose up, or equivalent.
Alternatively, if your databases are on a filesystem that supports snapshots (LVM, btrfs or ZFS for instance), you can make a snapshot of the filesystem, mount the snapshot and backup thame database from it. This will ensure the backup is consistent with itself (the backed up directory was not written to between the beginning and the end of the backup)