[Dovecot] questions about process_limit

[Andreas Meyer]

Hello all!

# dovecot --version
2.1.17

Sometimes I have this in the logfile:

May 11 16:55:52 master: Warning: service(imap-login): process_limit (100) reached, client connections are being dropped
May 11 17:35:03 master: Warning: service(imap-login): process_limit (100) reached, client connections are being dropped
May 11 17:36:27 master: Warning: service(imap-login): process_limit (100) reached, client connections are being dropped

I then put this in the dovecot.conf

service imap-login {
  service_count = 1
  process_min_avail = 50
  #process_limit = $default_process_limit
  process_limit = 10000
  vsz_limit = 64M
}

and get this:

May 11 18:19:36 master: Info: Dovecot v2.1.17 starting up (core dumps disabled)
May 11 18:19:36 config: Warning: service auth { client_limit=1000 } is lower than required under max. load (10300)
May 11 18:19:36 config: Warning: service anvil { client_limit=1000 } is lower than required under max. load (10203)

Puting this in:

service auth {
client_limit = 10300
    unix_listener auth-userdb {
      mode = 0666
      user = vmail
      group = vmail
    }
}

service anvil {
client_limit = 10300
}

I get this:

May 11 18:27:37 delta.bitcorner.eu dovecot[3989]: Warning: fd limit (ulimit -n) is lower than required under max. load (1024 < 10300), because of service auth { client_limit }

I have also seen this today:

May 11 13:14:05 log: Warning: Killed with signal 15 (by pid=1 uid=0 code=kill)
May 11 13:14:05 auth: Error: read(anvil-auth-penalty) failed: EOF
May 11 13:14:05 auth: Error: net_connect_unix(anvil-auth-penalty) failed: Permission denied

What is the best way to avoid this process_limit errors and configure
dovecot the best way?

Greetings

  Andreas