c) what Anti-Virus and Anti-Spam tools are you using
AntiVirus is clamav-0.75.1 and AntiSpam is SpamAssassin-2.63 with patched version of qmail-scanner "Qmail-Scanner-1.23st (st patch)" from http://xoomer.virgilio.it/j.toribio/qmail-scanner/. This patched version of qmail-scanner has been used to selectively enable only 20% of the domains to have AntiVirus/AntiSpam enabled. I am also using the "--sa-reject" option to have spam messages with a score higher than sa-delete (score of 16 in my case) to be rejected before the smtp session is closed.
I'd probably point the finger at qmail-scanner. It's a major resource hog and starts a perl instance every time a message comes in.
I use clamav and SpamAssassin as well, but use qscanq (google for it) and qmail-spamc (included with SpamAssassin) to block viruses and score spam on messages at the qmail-queue stage. Unfortunately, without patching, you won't be able to selectively enable it per domain or have an sa-reject option.
You could look at some of the patches Ken Jones of Inter7 has put together to add SpamAssassin integration to vdelivermail. This would offload the spam processing from qmail-smptd, and can be enabled on a per-domain basis. You could then replace qmail-scanner with qscanq to block viruses (for all domains) at the smtpd level.
- It might me worthwilhe to reduce the incoming-concurrency. Drop it to 30.
Any figures less than 80 would cause lot many Servers not to get smtp connect to our Server during peak time of 0100 to 0500 hrs EDT.
Maybe not. You need to determine whether a lower concurrency will reduce the amount of time spent on each message and ultimately allow more connections per hour. Once you start hitting virtual memory, all of the current connections will get bogged down.
Take a look at how many messages are processed per hour at 100, and then at 80. If the queue is growing and messages aren't getting delivered, there's not much benefit to queueing the message instead of just not accepting the connection.
-- Tom Collins - [EMAIL PROTECTED] QmailAdmin: http://qmailadmin.sf.net/ Vpopmail: http://vpopmail.sf.net/ Info on the Sniffter hand-held Network Tester: http://sniffter.com/