Quoting Dirk-Willem van Gulik <di...@webweaving.org>:
On 14 Aug 2018, at 09:38, Michael Menge
<michael.me...@zdv.uni-tuebingen.de> wrote:
Quoting Dirk-Willem van Gulik <di...@webweaving.org
<mailto:di...@webweaving.org>>:
On a smal cyrus imap 2.5.3 setup (freebsd ports, default settings,
5k users, 300 Gb mboxes) we are seeing very sporadic `loss' of
messages (once every few months; 1 or 2 messages; out of a few
100k to a million going through perfectly fine in the same period).
They disappear; but are still present as a /var/spool/imap/user/X/12345.
files.
But cannot be found; even when searching through IMAP on
message-ID or otherwise unique elements. Searches in the same
veign for the messages before/after the lost one work and return
those.
A grep through the cyrus.index shows its unique message ID.
A full reconstruct with /-r/-R/-G does not seem to bring it back
as visible.
The mesaages lost are otherwise normal; fully valid mime; and when
re-injected - pass through and surface.
What is the right way to debug this ? We suspect it may have
something to do with either (al)pine and thunderbird; as it seems
to hit users that mix those two clients - during periods they use
both. All else seems normal.
Do you use delayed expunge mode (man imapd.conf see expunge_mode)?
If yes, "unexpunge -l user/X" will show you the mails that have
been deleted but are still on the disk.
You will also see the time the mail was deleted.
Yes we do. And did not know about that command.
Where is this recorded / what rebuilds this file (and no - in this
case - it was not deleted, we do use delayed expunge) ?
The idea behind delayed expunge is twofold, on one hand it postpones
the I/O to an more convenient time, where less interactive I/O is done,
and on the other hand it is very useful for backup/restore as you can
keep the messages for a few days so that your normal backup has a chance
to see the deleted mails even if the user (op a POP3 client) did delete
before the backup is run. As a additional benefit you can restore these
mails very easy with unexpunge (see the manpage for details)
We use the unix hierarchy separator "/" (imapd.conf unixhierarchysep: 1)
which is not the default for Cyrus 2.5. If you do use "." als
hierarchy separator
you have to use "unexpunge -l user.X"
For more information about this take a look at
https://www.cyrusimap.org/2.5/imap/features/delayed-expunge.html
as well as the imapd.conf manpage ( deletedprefix, delete_mode,
expunge_mode, expunge_days) and cyr_expire manpage.
Regards,
Michael
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