ADSM-L

Re: Seeking thoughts on Cyrus email backup/restore

2006-05-16 10:48:37
Subject: Re: Seeking thoughts on Cyrus email backup/restore
From: Thomas Denier <Thomas.Denier AT JEFFERSONHOSPITAL DOT ORG>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Tue, 16 May 2006 10:48:15 -0400
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.