corrupt header and index files and mailbox.db problem with cyrus-imap-2.0.16 (lengthy)

[Andreas Piesk]

i'm running cyrus-2.0.16 wih db3-3.2.9 on debian linux 3.0 (glibc-2.2.5).

fairly often (every 1-2 days) a user has trouble wih some mail folders.
he or she cannot do any operation on the folders. the solution so far is 
to remove all cyrus.* files in that folder and run reconstruct. there 
are no entries in the logfiles indicating a problem. the filesystem is ext3.

what can cause the corruption and how could i prevent it?

yesterday i was forced to restart the cyrus-imap server. a user could 
not access his inbox (see problem above). the reconstruct didn't return. 
delivery processes didnt return. i tried to get a mailbox list using 
cyradm, no success but i got the following error message:

# grep DBERROR /var/log/imapd.log
Sep 24 16:54:15 thurn imapd[26923]: DBERROR: error closing: 
DB_INCOMPLETE: Cache flush was unable to complete
Sep 24 16:54:15 thurn imapd[26923]: DBERROR: error closing mailboxes: 
cyrusdb error
Sep 24 16:54:46 thurn imapd[28686]: DBERROR db3: 2 lockers
...
Sep 24 17:07:20 thurn lmtpd[28042]: DBERROR db3: 10 lockers
...
Sep 24 17:14:40 thurn reconstruct[30462]: DBERROR db3: 15 lockers
...
Sep 24 17:20:03 thurn ctl_mboxlist[30761]: DBERROR db3: 20 lockers
...
Sep 24 17:42:50 thurn imapd[31137]: DBERROR db3: 43 lockers

so i think, the problem is/was the mailbox db. i looked at pid 26923 and 
found the following:

#grep 'imapd\[26923\]' /var/log/imapd.log
Sep 24 16:37:35 thurn imapd[26923]: accepted connection
Sep 24 16:54:15 thurn imapd[26923]: Connection reset by peer, closing 
connection
Sep 24 16:54:15 thurn imapd[26923]: DBERROR: error closing: 
DB_INCOMPLETE: Cache flush was unable to complete
Sep 24 16:54:15 thurn imapd[26923]: DBERROR: error closing mailboxes: 
cyrusdb error

so it seems imapd was unable to finish the db operation because the 
connections was terminated from the remote side (i'm just guessing).

what could i do in such cases apart from restarting?

would you suggest upgrading to 2.1.9? i'm reluctant to do such a major 
upgrade if i'm not sure it solves my problems.

thanks for your time.

-ap

-- 
Andreas Piesk, Netzwerkadministration
Heise Zeitschriften Verlag GmbH & Co KG
Helstorfer Str. 7, D-30625 Hannover
Mail: api at heise.de Fon: +49 511 5352-477