Quoting Timo Sirainen tss@iki.fi:
You could try saving a backup of dovecot-uidlist periodically and when this happens again, see what exactly changed in the file.
Well actually I have hourly/weekly/monthly ZFS snapshots of all data
so I can do this now. Here I can see that the UID changed between week
13 and 14 of 2011:
./.zfs/snapshot/WEEK13_2011/ukgrid.net/a.smith/dovecot-uidlist:1815
W5772 S5627 :1238145250.H86871P67126.mx1.ukgrid.net:2,RS
./.zfs/snapshot/WEEK14_2011/ukgrid.net/a.smith/dovecot-uidlist:40723
W5772 :1238145250.H86871P67126.mx1.ukgrid.net
I believe this was due to an upgrade from Dovecot 1.2 to 2.0. Its the
only change I can see of the UID in 2011 apart from when I deleted the
dovecot-uidlist last Thursday. The incorrect ordering could have been
occuring since the upgrade to 2.0 but I just didn't notice it. I was
particularly worried about it as we have a long time issue with
blackberry users being resent large chunks of email and I was
wondering if this was the cause...
The issue did reoccur after deleting the dovecot-uidlist last Friday,
in that I had very old messages being listed in the top hundred or so
emails. Unfortunately I didn't make a note of the which messages these
were and all seems to be being listed correctly currently.
I am now armed with the knowledge to investigate this if it happens again.
One last thing, you asked previously if I used NFS and I said that in
this case I wasn't. We do have NFS and we do want to use it under some
circumstances with Dovecot, both server and client are FreeBSD 8.2,
are there any known issues with that in conjunction with Dovecot?
thanks Andy.