Eric Vaughn put forth on 10/5/2009 7:17 PM: > Are there any new features to postfix 2.6.x that would cause it to be slow? > > Other than the obvious suspects; stress adaptive behavior, logging, > ulimit (running out of file descriptors). > > We are a very high volume site, we use postfix only as a proxy to > decrypt TLS and then pass traffic downstream to other clients.
[snip] Is the new server plugged into the same switch port(s) as the old server, or a different switch port, or another switch entirely? Have you confirmed the NIC(s) are running at the same link speed as the old server, and running FDX and with no/minimal packet loss? Have you swapped patch cables yet? Is the new server bound with the same IP address(es) as the old server, and if not, is it on the same routing subnet as the old server? If the disk is SCSI, have you confirmed the controller and disk are sync'ing at the highest mode supported by each? Are you using any kind of remote lookup (e.g. LDAP) per connection to a remote host that might be injecting latency possibly due to a different network path than before? Are you doing a DNS lookup (or multiple) per connection that may now be injecting latency for some reason, different route maybe? Did you point the new host at a different set of DNS servers than the old host? Is the kernel tick rate (config_hz) different going from CentOS 5.0 to 5.3? Are there any other kernel or daemon timing difference between 5.0 and 5.3? That's about all I can think of for now. You've probably already covered all of these but I'm throwing them out there just in case. I've been in your shoes before, and sometimes it's something "obvious" that we just completely overlook, then pull our hair out (if you have any unlike me) for days until the solution pops into our heads. Good luck. -- Stan
