We have had a problem recently with dovecot corrupting it’s index files. I do not know exactly when this started. The version that Ubuntu provides is 2.3.11.
I recently changed the mail client server from keeping things on an NFS mounted partition to local disk as the general consensus within the dovecot community seemed to suggest this was a NFS related problem.
However, that did not resolve the issue. Today I compiled the most recent version, 2.4-devel and installed it. I also changed the locking from fcntl to dotlock which is slower but generally considered more reliable.
Getting the mail server off of NFS did not stop it corrupting it’s dovecot-index files. It is down presently as I’m trying to compile the current version to see if it is improved.
My last attempt to change the way the mail system is organized failed because the kernel we were using had a bug that caused it to incorrectly read the partition tables.
The kernel problem has been corrected. I am going to take mail down for about an hour now to move to igloo and to attempt to change the way it is structured to get the spool off of NFS for the client server because dovecot used to provide imap and pop3 has some issues working properly in an NFS environment.
During this time you will be able to read mail on shell servers but not via webmail, imap, or pop-3 and you will be unable to send mail. This work should be completed by 10PM.