[CentOS] Rsync and differential Backups

Mon Nov 9 16:26:01 UTC 2015
melkor.kp <melkor.kp at gmail.com>


For backups with rsync a recommend you to follow the approach discussed on
this website.
It provides you everything for getting a full backup and then the
incremental ones (deltas) using rsync.
The only thing you need in order to do that is that the hosting filesystem
supports hard links,


Roberto Nebot

2015-11-09 17:01 GMT+01:00 Alessandro Baggi <alessandro.baggi at gmail.com>:

> Hi list,
> how to perform a differential backup using rsync?
> On web there is a great confusion about diff backup concept when searched
> with rsync.
> Users says diff because it copy only differences. For me differential is
> backup from last full backup.
> Other users says that to perform a differential backup I must include in
> rsync command: --backup --backup-dir=/some/path but from manual page of
> rsync:
> #############
> --backup-dir=DIR
>               In combination with the --backup option, this tells rsync to
> store all backups in the specified directory on the receiving side. This
> can be used for incremental backups.  You can additionally specify a backup
> suffix
>               using the --suffix option (otherwise the files backed up in
> the specified directory will keep their original filenames).
> ....
> ###################
> Then at this point, I can perform a full backup copying base dir after
> last incremental. I can performa an incremental backup saving change on a
> specified destdir (using --backup-dir).
> How I can perform a diff backup?
> I know that rsync check differences using "the base dir". This dir have
> "the same content" of backupped source. To make incremental, this base is
> used.
> Supposing that I've 500 GB data on source. Make/sync the base-dir of 500GB.
> Running a full backup (the result file must be a fullbackup.tar.gz), at
> the end of the process I get a base-dir of 500GB and a .tar.gz of +/- 500GB
> compressed. Is correct make full backup, performing first an incremental
> backup on the base-dir and then compress it on a .tar.gz? Or is better
> resync all source in alternative destdir?
> In this example I've spent the double space for a full and a base-dir.
> 500GB Source vs 1TB for base-dir and a full.tar.gz. There is a way to
> performs other operation (incr and diff) without using the base and save
> disk space?
> Thanks in advance.
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