Massive LMTP Problems with dovecot

[Ralf Hildebrandt]

Currently I'm having massive problems with LMTP delivery into dovcot.
dovecot/lmtp processes are piling up, eas using considerable amounts
of CPU:

# ps auxwww|fgrep dove

root     20537  0.0  0.0  18124  1196 ?        Ss   15:18   0:00 /usr/sbin/dovecot -c /etc/dovecot/dovecot.conf
dovecot  20541  0.0  0.0   9620  1084 ?        S    15:18   0:00 dovecot/anvil
root     20542  0.0  0.0   9752  1264 ?        S    15:18   0:00 dovecot/log
root     20544  0.0  0.0  21168  2276 ?        S    15:18   0:00 dovecot/config
copymail 20580 72.8  0.0  39556  7036 ?        R    15:18   2:00 dovecot/lmtp
dovecot  20582  0.0  0.0  18568  1756 ?        S    15:18   0:00 dovecot/auth
copymail 20597 77.2  0.0  35688  5136 ?        R    15:18   2:06 dovecot/lmtp
copymail 20598 39.3  0.0  38060  5596 ?        R    15:18   1:04 dovecot/lmtp
copymail 20613 62.3  0.0  38036  5600 ?        R    15:18   1:41 dovecot/lmtp
copymail 20619 56.4  0.0  37732  7448 ?        R    15:18   1:31 dovecot/lmtp
copymail 20620 75.9  0.0  35872  5336 ?        R    15:18   2:03 dovecot/lmtp
copymail 20627 37.8  0.0  36480  5892 ?        R    15:18   1:01 dovecot/lmtp
copymail 20838 60.5  0.0  35640  5036 ?        R    15:19   0:59 dovecot/lmtp
copymail 20840 66.3  0.0  35920  5296 ?        R    15:19   1:04 dovecot/lmtp
copymail 20841 66.0  0.0  37456  6852 ?        R    15:19   1:04 dovecot/lmtp
copymail 20842 64.5  0.0  36424  5808 ?        R    15:19   1:02 dovecot/lmtp
copymail 20843 67.6  0.0  39612  7064 ?        R    15:19   1:05 dovecot/lmtp

doveadm stop won't stop these, I have to use kill -9 on them.
I already tried disabling fts (entirely), still things won't speed up.

I can't strace:
# strace -p 20841
Process 20841 attached

(and that's it)

# dpkg -l|grep dovecot
ii  dovecot-core                        2:2.2.25-1~auto+57    amd64 secure POP3/IMAP server - core files
ii  dovecot-imapd                       2:2.2.25-1~auto+57    amd64 secure POP3/IMAP server - IMAP daemon
ii  dovecot-lmtpd                       2:2.2.25-1~auto+57    amd64 secure POP3/IMAP server - LMTP server
ii  dovecot-lucene                      2:2.2.25-1~auto+57    amd64 secure POP3/IMAP server - Lucene support
ii  dovecot-sieve                       2:2.2.25-1~auto+57    amd64 secure POP3/IMAP server - Sieve filters support

I also tried deleting the mdboxes, that also didn't change anything. 
Ideas?

-- 
Ralf Hildebrandt
  Geschäftsbereich IT | Abteilung Netzwerk
  Charité - Universitätsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt at charite.de | http://www.charite.de