Re: [Duplicity-talk] --remove-older-than: what obvious thing am I missing?

[Dan Parrish]

Eric Hanchrow wrote:
> I've use this script to do periodic unattended backups to a couple of
> remote hosts to which I've got ssh access.
>
>     #!/bin/sh
>
>     # Is today Sunday?
>     if test `date +%w` = 0; then
>         howmuch=--full
>     else
>         howmuch=--incremental
>     fi
>
>     for host in one.host.com another.host.net etc.you.get.the.picture
>       do
>       echo $host ...
>       duplicity \
>           $howmuch \
>           --remove-older-than $(date +%s --date='last week') \
>           --include $HOME/one-important-directory \
>           --include $HOME/another-important-directory \
>           --exclude '**' \
>           $HOME \
>           scp://$host/dups
>     done
>
> It seems to work fine (i.e., the "dups" directories on those hosts are
> filling up nicely with impressive-looking backup files) except for one
> thing: those backup files never get deleted.  I'd thought that by
> specifying --remove-older-than, files older than a week would get
> pruned, but it ain't happening.  Am I misunderstanding something?
>
> This is version 0.4.1-8 on Debian Sarge (aka "Testing").

When I use the "--remove-older-than 10D" switch, this is what the output 
says:

There are backup set(s) at time(s):
Sun Dec 12 20:06:02 2004
Mon Dec 13 04:53:01 2004
Tue Dec 14 04:53:01 2004
Wed Dec 15 04:53:01 2004
Thu Dec 16 04:53:01 2004
Fri Dec 17 04:53:01 2004
Sat Dec 18 04:53:01 2004
Sun Dec 19 04:53:01 2004
Mon Dec 20 04:53:01 2004
Tue Dec 21 04:53:01 2004
Wed Dec 22 04:53:01 2004
Thu Dec 23 04:53:01 2004
Sat Dec 25 04:53:02 2004
Sun Dec 26 04:53:01 2004
Mon Dec 27 04:53:01 2004
Tue Dec 28 04:53:02 2004
Wed Dec 29 04:53:01 2004
Thu Dec 30 04:53:01 2004
Fri Dec 31 04:53:01 2004
Sat Jan  1 04:53:01 2005
Sun Jan  2 04:53:01 2005
Mon Jan  3 04:53:01 2005
Tue Jan  4 04:53:01 2005
Wed Jan  5 04:53:01 2005
Thu Jan  6 04:53:01 2005
Fri Jan  7 04:53:01 2005
Sat Jan  8 04:53:01 2005
Mon Jan 10 04:53:01 2005
Tue Jan 11 04:53:01 2005
Wed Jan 12 04:53:01 2005
Which can't be deleted because newer sets depend on them.
No old backup sets found, nothing deleted.


IOW, it doesn't prune like rdiff-backup does.  rdiff-backup keeps a 
current full copy and reverse diffs going back in time, while duplicity 
STARTS with a full backup and tracks the changes along the way.  Because 
of the way it tracks the changes, it can't prune the older tarballs.  I 
haven't figured out a way around this...There might be one, but I 
haven't read about it in my (admittedly light) reading of the man page 
and such.

As I figure it, your backup directory continues to get larger and larger 
over time, until you make a completely new backup ***OR*** you delete 
all increments since the last full backup and start building new 
incrementals.

Anyone else got this figured out?  I really liked how rdiff-backup 
handles everything...It's just not encrypted.

-Dan