[Dovecot] do not lose mail when dovecot is dead

[Daniel]

Hi!

Recently I've experienced problems with dovecot. Dovecot died silently, 
what means is that there are no core files, nor any indication in the 
log files, just the "kevent(): Invalid argument" messages. Dovecot just 
died, so deliver could not connect to the auth-master socket, which 
means that messages couldn't been delivered. The problem is that 
postfix thought that the delivery was successful, and didn't place the 
message to delay, but deliver(LDA) couldn't deliver the message, so it 
got lost.

An example:
postfix/pickup[29619]: 8A1C6F261: uid=1001 from=<id>
postfix/cleanup[19148]: 8A1C6F261: 
message-id=<20080107192402.8A1C6F261 at domain.hu>
postfix/qmgr[29441]: 8A1C6F261: from=<id at domain.hu>, size=585, nrcpt=1 
(queue active)
deliver(leva): Loading modules from 
directory: /usr/local/lib/dovecot/lda
deliver(leva): Module 
loaded: /usr/local/lib/dovecot/lda/lib10_quota_plugin.so
deliver(leva): Module 
loaded: /usr/local/lib/dovecot/lda/lib90_cmusieve_plugin.so
deliver(leva): Can't connect to auth server 
at /var/run/dovecot/auth-master: Connection refused
postfix/pipe[8582]: 8A1C6F261: to=<leva at domain.hu>, orig_to=<id>, 
relay=dovecot-lda, delay=1.7, delays=1.1/0/0/0
.68, dsn=2.0.0, status=sent (delivered via dovecot-lda service)
postfix/qmgr[29441]: 8A1C6F261: removed

See? Postfix removed it from the queue, so basically all bets are off, 
and everything depends on deliver, but it just dropped the message.
Is there anything that can be done regarding this issue?

Thanks!

Daniel