[ext] dovecot/imap hohe io load

[Ralf Hildebrandt]

* Simon Sutter <ssutter at hosttech.ch>:
> Hallo Ralf, hallo Hajo
> 
> Danke vielmals mit dem Tipp für das Log.
> Ich habe es nun eingeschalten und heute war es wieder so weit, dass der Server wieder ins Stocken kam.
> Laut atop ging das Ganze von 08:07 Uhr bis 08:17 Uhr.

In dem Zeitraum sieht man:

Nov  8 08:09:24 301 dovecot: service=imap, user=[], ip=[]. Warning: Transaction log file /var/qmail/mailnames/account/user/Maildir/dovecot.index.log was locked for 63 seconds (appending)
...
Nov  8 08:09:24 301 dovecot: service=imap, user=[], ip=[]. Disconnected in APPEND (1 msgs, 0 secs, 0/12517 bytes) rcvd=178285, sent=10232103
...
Nov  8 08:16:14 301 dovecot: service=lda, user=[], ip=[]. Warning: Transaction log file /var/qmail/mailnames/account/user/Maildir/dovecot.index.log was locked for 42 seconds (Mailbox was synchronized)
...
Nov  8 08:16:25 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 41 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)
Nov  8 08:16:25 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 41 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)
Nov  8 08:16:25 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 41 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)
Nov  8 08:16:25 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 41 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)
Nov  8 08:16:25 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 41 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)
Nov  8 08:16:25 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 41 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)
Nov  8 08:16:25 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 41 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)
...
Nov  8 08:16:28 301 dovecot: service=lda, user=[], ip=[]. Warning: Maildir /var/qmail/mailnames/account/user/Maildir: Synchronization took 42 seconds (1 new msgs, 0 flag change attempts, 0 expunge attempts)

Sieht für mich so aus als wäre da massiv Disk IO mit massivem IO wait!

-- 
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 | https://www.charite.de