[Dovecot] fstat no such file or directory error

[Mark Dieterich]

Periodically, we will have users IMAP sessions get hung.  Their client
sees a message like:

The server responded: 'SERVERBUG] Internal error occurred. Refer to
server log for more information

On the server, we see the following in the logs:

IMAP(<username>): Transaction log dovecot.index.log: duplicate
transaction log sequence (37)
IMAP(<username>): fscking index file dovecot.index
IMAP(<username>): fstat() failed with index file
dovecot.index: No such file or directory

After the fstat message shows up, there doesn't appear to be anything on
the user side that can be done to fix the problem.  We've seen multiple
instances where the file dovecot is complaining about not existing is
visible, readable, and writable by the user in question, but dovecot is
convinced it's not.  The only way we've found to fix this issue is to
kill off all user connections.  When the user reconnects, then all
appears to work fine.  We have not found a way to recreate this problem.

Some details:

# 1.2.15: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.26-2-686 i686 Debian 5.0.8

Mail files are stored on NFS.  All imap connections for a given user are
are mapped to a particular server at any given time.

We have a script in place that watches our logs for this order of
events, so the problem self corrects relatively quickly.  But it would
certainly be nice not have this happen at all.

Thanks,

Mark

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