On Feb 25, 2011, at 2:58 PM, Victor Duchovni wrote: > On Fri, Feb 25, 2011 at 02:38:16PM -0800, Robert Goodyear wrote: > >>> Have you seen problem relays in your upstream relay mix? What real >>> symptoms do they exhibit and what is the observed impact on the upstream >>> Postfix SMTP client? >> >> I'm going to run some analytics on my last 12 months' worth of outbound >> messages to get more scientific with my gut instincts here. It's about 270 >> million messages, and my observation is that when we have a spike of 4 or >> 5 million that need to deliver at a certain point in time (surrounding a >> critical/time-sensitive product launch) that my deferred queues saturate >> too quickly. > > 20 million a month is a moderate mail flow if it is mail from ~50-100K > users spread out over the day. I would then expect no more than ~1K > messages in the deferred queue of each ~4 machines to be about the right > quantity of deferred email. > > 4 million messages to deliver all at once is a very different problem.
It is definitely a lumpy distribution -- probably 2 to 3 per month of ~4-5 million to North American subscribers, interspersed with smaller regional (outside North America) campaigns of 250-300K that sometimes coincide with one of the big campaigns. Of course I could start building "stovepipes" in my topology to isolate activity so one doesn't affect the other, but then conversely I might have cold MTAs sitting idle when I could be using them. I *do* have some regional points of presence where I have MTAs close to the subscribers for their markets, e.g.: UK, EU and SE Asia; maybe I should experiment with offloading deferred North America queues to them. I wonder if their inherent latency would act as a rate limiter of sorts that would play more nicely with recipient domains? Anyway I'm speculating... let me go crazy with SPSS and look for some absolute patterns in the last year here.
