[OT] Re: What's the best possible email failover solution

[Bill Moran]

Christian Laursen <xi at borderworlds.dk> wrote:

> Bill Moran <wmoran at potentialtech.com> writes:
> 
> > Nico Meijer <nico.meijer at zonnet.nl> wrote:
> > 
> > > Hi Bill,
> > > 
> > > > The other option is to take what appears to be the best IMAP server out
> > > > there (Cyrus) and figure out a way to do real-time mirroring of the
> > > > mailboxes.
> > > 
> > > Depending on the size / number of messages: how about using rsync and 
> > > OpenBSD's CARP?
> > > 
> > > True, it will not be realtime, but the synchronization (note the 
> > > "depending" above) might take place regularly.
> > 
> > Problem is: rsyncing the mail directories takes about 20 minutes, and the
> > only way to ensure that a good copy is achieved is to shut down Cyrus
> > during the backup.  This makes it a little prohibitive to be doing this
> > very often.
> 
> If you are running FreeBSD 5, you should be able to make a filesystem snapshot
> and rsync from there.

I suppose I should have commented on that ;)

We're not running FreeBSD 5 on these production machines yet ... but it's
likely we will be soon, so I'm considering using snapshots.

To my understanding, we still have to stop Cyrus while the snapshot is
being created (to ensure consistency) but since a snapshot takes a lot
less time than an rsync, this should be a big improvement.  Once the
snapshot is created, rsync can take as long as necessary.

-- 
Bill Moran
Potential Technologies
http://www.potentialtech.com