...dropping the OS issue, which is not on-topic for this list. At 9:25 PM +0100 3/26/05, Brad Knowles wrote: >> (To be fair to the Powerbook, I was also asking it to be a laptop at the >> time. It could not handle heavy-duty web browsing at the same time >> it was handling peak Mailman loads. Moving VERP from Mailman >> to exim and setting up a caching name server solved the problem.) > >/me wonders how much of the performance difference was due to >letting Exim handle the VERP as opposed to setting up a caching >nameserver.
You're right that that caching nameserver made the biggest difference in terms of increasing network throughput (and decreasing timeouts). That was probably 2/3 of the performance right there, and it came off all delivery times, whether the system was busy or not. In terms of getting the mail into the users' mailboxes, having exim do the VERP processing decreased the elapsed time for digest deliveries from a mean of 60 minutes to a mean of 15 minutes. Mailman had to make many more connections to exim, and exim was unable to batch deliveries to the same host as efficiently as it can do when it does its own VERP processing. Turnaround on normal list deliveries was improved also, but not as dramatically. Exim could certainly be smarter about batching deliveries to the same host. It only seems to try for messages that come in on the same queue run, so it was better to have Mailman send all its digest runs in one lump sum (more or less) and then have exim churn through them than to have Mailman dole them out and exim handle them inefficiently. When I was having Mailman do its own VERP, I'd see exim do VERP checks repeatedly on the same address. When exim is doing the VERP, it still does some of this, but much less. -- Heather Madrone ([EMAIL PROTECTED]) http://www.madrone.com A rolling stone gathers no mass. ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org http://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://www.python.org/cgi-bin/faqw-mm.py Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: http://mail.python.org/mailman/options/mailman-users/archive%40jab.org Security Policy: http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq01.027.htp