I have been having problems with resouce utilization with one of my qmail servers, which basically boils down to reaching the concurrencylimit of tcpserver for my pop3 connections (60) and this brings the server to its knees. The only recourse I have left is to reboot, since even console is not responsive.
What happens if you set concurrencylimit to 30? Are people checking their email too often? Is the problem that the POP3 users take a long time to download their email (on dialup)?
I have checked my logs, and basically, for each pop3 connection, an instance of mysql is generated to check password for a virtual domain user, this generates swapping. The load average shoots up to 300 and I have seen this go as high as 500.
Are you sure there isn't something else happening on the machine that pushes the load up?
The server is running Linux RedHat 7.3 and has 512MB RAM and 1GB SWAP, for about 4000 users in 70 virtual domains. It also runs Apache for qmailadmin. Since there are not that many users per domain, less than 100 average, will CDB Files be a better solution to this problem?
Can this machine work with more memory? You could add another 512M or even 1G of RAM and alleviate the problem.
I'm sorry, but I don't know whether switching to CDB will help with your problem.
-- 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/