Marc Perkel wrote:
>>> I'd appreciate a few pointers towards mechanisms/packages/ideas for
>>> doing this to ensure I don't miss any possibilities.
>>>
>>> We have a requirement for a mail server (SMTP receive, POP collection,
>>> IMAP not currently required) with a presence in 2 data centres, and
>>> able to maintain operation if either data centre or the link between
>>> them is unavailable. The ability to reconnect disjointed data centres
>>> without data loss (we could tolerate some resurrection of deleted
>>> messages) would be needed. There would be a huge number of
>>> mailboxes, but low activity on each mailbox - aggregate activity is
>>> not that high.
>>>
>>> Any ideas or suggestions?
>>>
>>>
>> I used to have this kind of system working using unison
>> (http://www.cis.upenn.edu/~bcpierce/unison/) for the two way replication.
>> Assuming the messages don't change once they are written to disk, you can
>> configure unison with a good performance. I would suggest you to take the latest
>> development version of unison as it has some improvements on how conflicts can
>> be solved if they occur.
>> You will of course need to use a Maildir storage for this to work.
>
> That unison looks interesting. I'm just wondering - is it better than
> just running rsync if you just want to get a backup of maildir
> directories every hour or so?
Unison remembers state between runs and thus does two way
synchronisation. What you described sounds like it only needs one way
syncing. So rsync is probably sufficient.
I use unison to keep a subversion repository in sync across two boxes.
You can commit changes to either box, and unison makes sure it copies
across to the other box.
--
Mike Cardwell
(
https://secure.grepular.com/) (
http://perlcv.com/)
