Quoting Thomas Denier <Thomas.Denier AT JEFFERSONHOSPITAL DOT ORG>:

Richard Sims ----- wrote: -----

For planning purposes, I'd like to get input from Cyrus sites as to
issues they've encountered in performing backups and restorals,
particularly with coherency, given that each message becomes an
individual file. The Many Small Files issue is apparent, but there
are probably other things that sites have learned the hard way that
could help others. One unobvious issue I can think of is how to best
perform mail investigations via restorals, as called upon in
subpoenas. (A search of the ADSM-L archives turns up next to nothing
on Cyrus and TSM.)

My department provides TSM coverage to a Cyrus mail server
administered by another department. Each mail directory on a Cyrus
system contains an index file. When we started there were a lot
of problems with index files that changed while the backup was
in progress. The Cyrus administrators opted to exclude the index
files. There is a Cyrus utility that will scan the message files
and rebuild the index files. They use this to recreate index files
after restores.

I am not sure how long it would take to rebuild all the index files
if the whole system had to be restored. The Cyrus administrators
once rebuilt all the index files to clean up corrupt data produced
by a Cyrus bug. It took days. They think an index file rebuild after
a full restore from TSM would be much faster. I am not sure why they
think this.

we also want to avoid the cyrus 'reconstruct' utility and
use a snapshot of the logical volume for the backup.

With PRESCHEDULECMD we start a script where we
    - stop cyrus and postfix
    - create the snapshot (lvcreate --snapshot ...)
    - start cyrus and postfix
    - mount the filesystem(s) on the snapshot

Then we do the normal file level backup on the snapshot
after that we remove the snapshot with POSTSCHEDULECMD.


--
Karl Rößmann                          Tel. +49-711-689-1657
Max-Planck-Institut FKF                 Fax. +49-711-689-1198
Postfach 800 665
70506 Stuttgart                         email K.Roessmann AT fkf.mpg DOT de