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. (master.cff:smtpd -o smtpd_proxy_filter=x.x.x.x) Primary symptoms: New server (2.6.3) is running much slower than old system was (2.5.1). CPU utilization is much lower There are no errors in the logs. Not even with verbose logging turned on. (We have since disabled verbose logging for performance reasons.) There seems to be a ~3.5 second latency for both connection establishment and transaction completion. (We have yet to identify the source of this latency.) Here is a list of things we have checked so far: Stress adaptive behavior (has not turned on) Logging (syslog.conf - was a good suspect, syslog.conf was cleaned up and performance is still slow.) ulimit (new postfix allows much higher number of open files per process, this was increased to 4096) disk i/o (sar and iostat) ssl (is not suspect because cpu utilization is low) default process limit was increased to 2000 during the upgrade (main.cf:default_process_limit = 2000) - This could be a good source as well if downstream clients are not able to handle high concurrency, we will lower to 1000 for retesting. I wish I had a list of specific questions to ask. Unfortunately due to the lack of information in the logs, there isn't much to go on. Thank You - Eric
