On 11/27/07, Christopher Adams wrote: > One concern - Charles mentioned how 'expensive' it was to use VERP > with Postfix. I am wondering what kind of hit on the responsiveness of > my Mailman server will be.
There has been some research on this topic, which is summarized at <http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq04.012.htp>. > I have over 500 lists and 250,000 > subscribers. That would be one of the larger mailing lists known to be running Mailman, see <http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq01.015.htp>. > If VERP being used for Mailman causes more mail activity, > could this result in slowness of list message delivery? Well, it all comes down to how much activity your lists have. A list that has hundreds of thousands of subscribers but which only gets one post per month is not necessarily going to see the same sets of performance problems as a site that has a smaller number of lists with a smaller number of recipients, but where the lists are very active. For that second URL shown above, contrast the profiles of HostMySite.com and panic.com as compared to lists.apple.com and FreeBSD.org. Going back to that first URL shown above, I think the most critical summary paragraphs are these: The network penalty between SMTP_MAX = 1 (effectively VERP) and any kind of batching (SMTP > 1) is roughly 50%. To get VERP or customized footers or customized anything, you double your network bandwidth. There is very little advantage to setting SMTP_MAX > 5, UNLESS your subscriber base is heavily stratified onto very few sites. If you have really large groups of subscribers on AOL or Hotmail, it can help cut network bandwidth, but at best, it seems to be about a 10% improvement. Keep in mind that this is for the test set described, but we believe that this is a reasonably accurate description of many Mailman mailing list servers & services. -- Brad Knowles <[EMAIL PROTECTED]> LinkedIn Profile: <http://tinyurl.com/y8kpxu> ------------------------------------------------------ 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
