Re: Backups w/ rsync

[Michael Tokarev <mjt@tls.msk.ru>]

Dean S. Messing wrote:
> Michael Tokarev writes:
[]
> : the procedure is something like this:
> : 
> :   cd /backups
> :   rm -rf tmp/
> :   cp -al $yesterday tmp/
> :   rsync -r --delete -t ... /filesystem tmp
> :   mv tmp $today
> : 
> : That is, link the previous backup to temp (which takes no space
> : except directories), rsync current files to there (rsync will
> : break links for changed files), and rename temp to $today.
> 
> Very nice.  The breaking of the hardlink is the key.  I wondered about
> this when Michal using rsync yesterday.  I just tested the idea. It
> does indeed work.

Well, others in this thread already presented other, simpler ways,
namely using --link-dest rsync option.  I was just too lazy to read
the man page, but I already knew other tools can do the work ;)

> One question: why do you not use "-a" instead of "-r -t"?  It would
> seem that one would want to preserve permissions, and group and user
> ownerships.  Also, is there a reason to _not_ preserve sym-links
> in the backup.  Your script appears to copy the referent.

Note the above -- "SOMETHING like this".  I was typing from memory,
it's not an actual script, just to show an idea.  Sure real script
does more than that, including error checking too.

/mjt