[CentOS] Rsync and differential Backups

Mon Nov 9 18:42:08 UTC 2015
m.roth at 5-cent.us <m.roth at 5-cent.us>

Gordon Messmer wrote:
> On 11/09/2015 09:59 AM, John R Pierce wrote:
>> On 11/9/2015 9:50 AM, Gordon Messmer wrote:
>>> I don't see the distinction you're making.
>> a incremental backup copies everything since the last incremental
>> a differential copies everything since the last full.
> I guess that makes sense, but in backup systems based on rsync and hard
> links (such as rsnapshot), *every* backup on the backup volume is a
> "full" backup, so incremental and differential are the same thing.
>> rsync is NOT a backup system, its just a incremental file copy
> ..which can be used as a component of a backup system, such as rsnapshot
> or backuppc.

Actually, we use rsync for backups. We have a script that creates a new
daily directory... and uses hard links to previous dates. That way, it
looks like a full b/u... but you can go to a previous date to restore an
older version of the file (aka ACK! I saved that file full of garbage to
my Great American Novel filename! <g>).

And if you aren't familiar with hard links, which rsync happily creates,
they were certainly hard enough to wrap my head around, until I got it...
and really like them. Just note that they *must* be on one filesystem, as
opposed to symlinks, which can cross filesystems.