Preparing for Testing

System configuration

  • Make sure your firewall is configured to allow incoming connections for the following tcp ports: 24, 110, 143, 993, 995, 4190.

  • Ensure ulimit is high enough to accept all the connections and open files.

Dovecot configuration

Enable LMTP delivery times in the configuration:

deliver_log_format = msgid=%m from=<%f> size=%p vsize=%w session=%{session_time}ms delivery=%{delivery_time}ms: %$

You can then see log entries like:

Oct 06 12:40:13 lmtp(<iQBSCwulE1ZXMwAA0J78UA>: Info: iQBSCwulE1ZXMwAA0J78UA: msgid=unspecified from=<> size=155980 vsize=157963 session=161ms delivery=134ms: saved mail to INBOX

Increase the maximum user connections per IP

mail_max_userip_connections = 1000

Object Storage

Reducing the fscache value in obox_fs will result in more load for your storage platform. The fscache / ftscache should always be on tmpfs.


You might run into problems where you have too few services running and you need to increase the number of services and/or modify client limit for the following:

  • auth

  • imap

  • pop3

  • lmtp

  • metacache

  • metacache-worker