keep cyrus in sync with cold standby

[Marcus Schopen]

Hi,

I'm thinking about a strategy to keep my cyrus server (2.2.13 on Ubuntu
10.04 LTS) in sync with a cold standby server. This hasn't to be a
live/hot sync and I'd like to keep it as simple as possible. A sync
delay up to 30 minutes is acceptable for this small setup (250 Accounts,
80 GB mail storage, 5 emails per minute), but I don't want to stop cyrus
while doing the snyc.

Cyrus replication seems to be the most reasonable way, but I'm sitting
on Ubuntu 10.04 LTS, which comes with cyrus 2.2.13 and I can't find any
newer backports. Centos 6.x with Cyrus 2.3.16 could be an alternative
setup, but I'm not sure if 2.3.16 is also to old for stable
replication. :/

DRBD could be an option but I never had DRBD running within a parallels
virtualisation (bare metal setup); might be a timing/performance problem
with a lot of very small files?

Do I run in bad problems if I just run a simple rsync
of /var/lib/cyrus, /var/spool/cyrus/ and /var/spool/sieve/ and dump
mailboxes.db (skiplist) with "ctl_mboxlist -d" every 30 minutes? Is
there a way give cyrus a flush of its databases without stopping it?

Ciao
Marcus