Btrfs: Subvolumes and snapshots

Posted Jan 28, 2014 16:00 UTC (Tue) by nye (subscriber, #51576)
In reply to: Btrfs: Subvolumes and snapshots by janecek
Parent article: Btrfs: Subvolumes and snapshots

You would also want --no-whole-file, because the default for local syncs is to rewrite the whole file rather than using the delta transfer algorithm.

Anecdote time:

I have a system which stores backups that come in the form of some large-ish database dumps created by some MS software. Each time the backup is made, the entire file is rewritten, thus defeating the use of snapshots for saving multiple versions with minimal disk space.
My solution to this is to save them to a staging area which does not get snapshotted, then 'rsync --inplace --no-W' to the final destination, which contains yesterday's version of the dump. This neatly turns a full rewrite into a much smaller set of block changes, without having to use some full-blown deduplication tool.