[Mailman-Users] Mailman throughput

Ivan Fetch ifetch at du.edu
Sun Aug 14 09:09:14 CEST 2011


I am trying to gage the capability of a Mailman virtual machine, which we will be moving our lists to. I'd like to do my best to size and tune this VM, and it's Postfix and Mailman installation, before putting it in production, and potentially having to troubleshoot and tune in a hurry.

What is a reasonable / realistic way to benchmark a Mailman installation? Are there details of other similarly sized instlalations and throughput numbers which I can compare?

We have 1300 mailing lists, and average 68000 posts to lists per day. We have lists as large as 7000 subscribers, but I'd say that the average size of a list is 500 subscribers (this number is a rough guess, based on some crunching of Mailman logs).

THe new VM will receive messages for mailing lists using Postfix. Mailman hands off to a separate box to deliver to list recipients. So Postfix on the Mailman VM will not be busy trying to deliver to subscribers.

I am sending some test messages through the VM, but don't know whether this is useful or pointless, in telling me how capable the VM is.

The VM processed 10000 messages in an hour and 10 minutes. The messages went to two lists, one with 25 recipients and the other with 500 recipients. The VM (Linux) peaked at a load average of 4 (2 VCPUs), and was using 800Mb of it's 2G ERAM for IO caching. I could add more resources, but it doesn't look like they would get used.

Initially (maybe for the first 15-20 minutes) the Postfix queue had to catch up submitting messages to Mailman. After that, qfiles/in was empty, and the work which remained was to process qfiles/out and SMTP the outbound messages to the relay. I raised SMTP_MAX_RCPTS from 500 to 1000, but this did not seem to make a difference.

SO I may be able to tune Postfix handing off to Mailman, as well as Mailman handing off to the SMTP relay. Any suggestoins here?

The current Mailman box runs SOlaris / Sparc. The Mailman processes use 1.2G of memory, and CPU (this is a Sunfire 880, 4 Ultrasparc III procs) hovers around 5%.




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