Michael, > On Freitag, 27. Juni 2008 David Schweikert wrote: > > I use amavisd-milter with postfix and it works very well. I did it so > > that I could implement pre-queue filtering efficiently: it has the > > big advantage that you can have 200 postfix smtpd processes, 1 > > amavisd-milter and (for example) 5 amavisd. Otherwise, with the > > smtpd_proxy_filter setup, you would also need 200 amavisd... > > Are there any side effects with this? Currently I use post-queue amavis, > but I've heard several times now that pre-queue is better for high > throughput.
Pre-queue is not better for throughput, at least not when a heavy-weight filter like SpamAssassin is in play. > Are the 5 amavisd for post-queue, or what? No, David keeps 5 processes available for pre-queue, the rest of 200-5 sessions are kept pending. Probably works most of the time as long as processing time is not too high, the number of concurrent sessions is not too high, and clients are willing to wait with a session connected. Not as predictable setup as a post-queue. > I don't understand the concept, why it is more effective. David was comparing it to smtpd_proxy_filter setup, not to a post-queue setup. > I know that I would > need 200 amavisd with post-queue, but why not with pre-queue? No, you don't, you got it in reverse. You'd need 5 (or maybe 25) in post-queue and still let postfix handle 200+ concurrent incoming sessions quickly and efficiently, obtaining a well-behaved setup even under high load conditions. With pre-queue you'd in principle need 200 content filters (or milter threads), unless a trick with an intermediate amavisd-milter is used which relaxes this condition to some extent, but under high rush-in the incoming sessions could still be in trouble. Mark ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ AMaViS-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/amavis-user AMaViS-FAQ:http://www.amavis.org/amavis-faq.php3 AMaViS-HowTos:http://www.amavis.org/howto/
