Noob question:

let's say I have two identical drives, A and B.

Let's say I want to reduce data loss chances to a minimum.

Would it be better to:
1) setup a zfs mirror with both A and B
2) schedule a recurrent rsynch backup from A to B

Boosts most welcome :)


2) rsync to the second drive (zfs/btrfs fs with hourly snapshots)

@cretox @Antanicus @Radamanth In our environment we use a straight rsync back-up, due to our users' needs: restoring single files and/or directories on demand

@desantis @cretox @Radamanth
Yes restoring files will be the likeliest scenario for my use too (a self-hosted nextcloud instance)


In that case, I'd suggest rsync since it is trivial to configure and you'd get immediate results. If you have the space, its incremental option is cool since it will only back-up changed files.

@cretox @Radamanth

The two drives are identical, so this should be a reasonable option, I guess (A can't overflow B if they are the same size, right?)
@cretox @Radamanth


As long as you don't use the incremental option, space will not be a concern. The incremental option will utilize more space and could lead to overruns if not policed.

@cretox @Radamanth

@Antanicus I suggest putting the second drive in a second computer, and using a backup tool like borg instead of rsync.

A second computer so that if the first one catches on fire, or you fumble a command as root, all is not lost.

Borg because rsync is not actually a particularly good backup tool.

Good luck!

@Antanicus It depends entirely on what you're trying to prevent. A mirror would be as good as a single copy on another disk if we're just talking disk failure.

But malware or accidental deletion isn't really prevented by either since you're only storing the lastest copy.

Better option may be to use something that can do versioned backups with compression and deduplication so you're more throughoutly covered in all cases.

@rune thanks! Could you point me to some resources on how to achieve versioning?

@Antanicus I use duplicati myself, but there are a number of options like borg backup and duplicity as well.

@Antanicus a zsf mirror might be better. I cannot imagine an rsync running every X hours to do much good for your machine's performance.

Also, if you set up a zfs mirror, that's hard-wired as fuck. An rsync cron job might fail/get deleted and then you're fucked. How often would you check "is it still running?" Don't know about you, but I'd slip that shit out of my head.

@Antanicus No problem.

NOTE: There is a high possibility I'm always wrong

@Antanicus @remotenemesis ZFS. Because hashing. Otherwise you might just copy over the corruption instead of detecting it and restoring the good file.

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