Hi,

we are running a 4 host setup which each hosts a director+mailbox which is mounted via NFSv4 from a DRBD cluster.

• Dovecot upstream release 2.1.16
• Doveadm batch subcommand fix - http://hg.dovecot.org/dovecot-2.1/raw-rev/850b5d8bbcc9
• Pigeonhole release 0.3.4

Now we would like to remove duplicate Mails using the vnd.dovecot.duplicate extension using a SIEVE script like this:

require ["vnd.dovecot.duplicate", "fileinto", "mailbox", "regex", "vacation", "variables"];

if duplicate { fileinto :create "Trash"; }

But as soon as we start delivering duplicate mails, we're sometimes getting locking errors from the mailbox (which is responsible for the user) according to the director:

Dec 27 16:36:30 10.129.3.213 dovecot: lmtp(27975, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:33 10.129.3.213 dovecot: lmtp(27987, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:35 10.129.3.213 dovecot: lmtp(27994, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:36 10.129.3.213 dovecot: lmtp(28011, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:36 10.129.3.213 dovecot: lmtp(28013, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:38 10.129.3.213 dovecot: lmtp(28017, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:39 10.129.3.213 dovecot: lmtp(28025, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:42 10.129.3.213 dovecot: lmtp(28037, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs Dec 27 16:36:43 10.129.3.213 dovecot: lmtp(27973, user001@example.org): Error: Creating lock file for /mail/dovecot/example.org/user001/.dovecot.lda-dupes timed out in 20 secs

Configs and Error log is attached.

Any idea how to mitigate these locking issues?

Regards Daniel