rsync - Dec 2006 - May I merge several increment backups to one?

Hi all,


I have the following situation:

Backup /mysource  to  /backupdir,

/backupdir/full ---------an old full backup

/backupdir/back2  -------previous increment backup(based on the full backup
mentioned above)

/backupdir/back1   ------most recent increment backup (based on the two
backups mentioned above)


How can I merge the two increment backups into one directory,say
/backupdir/increment ?


Best regards!

robbin
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On 12/5/06, woo robbin <robbinwooo@gmail.com>
wrote:
> How can I merge the two increment backups into one directory,say
> /backupdir/increment ?
In an "incremental backup", files matched in the previous backup are
omitted altogether, right?  So then all you need to do is copy all the
files from /backupdir/back2 and /backupdir/back1 into one directory,
where files from /backupdir/back1 override those from
/backupdir/back2.  This is easy to do with rsync (or with cp, for that
matter):

rsync -a /backupdir/back2 /backupdir/increment
rsync -a /backupdir/back1 /backupdir/increment

Does this answer your question, or have I misunderstood it?

Matt

On Wed, 06 Dec 2006 08:47:42 +0800, woo robbin wrote:
> How can I merge the two increment backups into one directory,say
> /backupdir/increment ?

I suggest you look into exploiting the --link-dest option in your backups.
Using this, each backup has the performance of an incremental (both in
terms of network and disk space utilization) but produces a complete
snapshot as if it had been a full.  This is achieved by hard-linking back
to the previous snapshot for any files not changed since that previous
snapshot.

Because these are hard links, it is safe to remove any previous snapshot;
it won't render a later snapshot unusable.  

Most, if not all, of the issues associated with incremental backups
disappear using this scheme, yet the performance is still
incremental-like.  And because complete snapshots are always produced,
there's no need for an occasional full backup (excluding the first backup
of any volume, of course).

	- Andrew