singleinstancestore obsolete?

Wolfgang Breyha wbreyha at gmx.net
Wed Oct 19 17:22:09 EDT 2011


On 2011-10-19 17:42, Simon Matter wrote:
> I think for the singleinstancestore, you can redo it after migration with
> tools like hardlink or http://www.freedup.org/. IIRC I did this once and
> it worked fine - I think I was using a simple bash script as you suggested
> above. The only problem could be that you need the extra space while
> migration is going on.

My first
find /var/spool/imap/partxx -type f -links +2 -printf
"%10i,%3n,%9s,%C@,%c,%T@,%t,%u,%g,%#m,%p\n"
finished and my current savings are 60GB on a 256GB(230 used) partition.
So, extra space is in fact a topic;-) This backend holds all our student
accounts. That's why the savings are that impressive.

With the list find provides I am able to run my short perl script several
times while migrating mailboxes to get space back very fast and with low IO
impact.

Running freedup(.org) is still a very good idea. Thanks a lot for the hint.
I tried it in dry run mode on one of my other backends containing only
XFERed mailboxes from our employees. It took about 2 hours to analyze a
256GB(165 used) partition with ~800k messages. Savings will be ~2,5GB. Not
that much, but still worth the time.

I used "freedup -n -v -a -T -o '-name "*."' -l /var/spool/......". Memory
usage was ~300MB on x86_64.

hardlink (at least the version provided with RHEL6) is not suitable since
it hardlinks many cyrus.index files together because I've to compare on
file contents only and there is no option to exclude them.

Greetings, Wolfgang
-- 
Wolfgang Breyha <wbreyha at gmx.net> | http://www.blafasel.at/
Vienna University Computer Center | Austria


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