rsync --link-dest and --files-from lead by a "change list" from some file system audit tool (Was: Re: cut-off time for rsync ?)
c182driver1 at gideon.org
Thu Jul 16 17:56:05 UTC 2015
On Tue, 14 Jul 2015 08:59:25 +0200, Paul Slootman wrote:
> btrfs has support for this: you make a backup, then create a btrfs
> snapshot of the filesystem (or directory), then the next time you make a
> new backup with rsync, use --inplace so that just changed parts of the
> file are written to the same blocks and btrfs will take care of the
> copy-on-write part.
That's interesting. I'd considered doing something similar with LVM
snapshots. I chose not to do so because of a particular failure mode: if
the space allocated to a snapshot filled (as a result of changes to the
"live" data), the snapshot would fail. For my purposes, I'd want the new
write to fail instead. Destroying snapshots holding backup data didn't
seem a reasonable choice.
How does btrfs deal with such issues?
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