[CentOS] Postfix smtp freezing

[Feizhou]

Jason Ross wrote:
> Hey all,
> 
> For the last 8 months I have been running a postfix / mail scanner setup 
> based on Johnny Hughes' excellent tutorial.
> For the firs 7 months I have had no issues. This past month I have been 
> having instances where the user gets an smtp error while trying to send 
> email.
> Restarting the postfix service is all it takes to resolve this issue. 
> The problem is that it has begun to occur more and more often. It is now 
> up to once every day.
> I have found nothing unusual in the mail or messages logs. As I am an 
> ultra newbie I am unsure of the next step to take to resolve this.
> I have search through the past messages on this list and can find 
> nothing. Anyone have any ideas?

The following details would be nice:

Number of smtpd daemons configured (if you have not changed then it is 
100), number of smtpds, cleanups and trivial-rewrites running when you 
encounter the problem, cpu utilization statistics.

I am not familiar with how mail-scanner is run. I assume it has a fixed 
number of processes. Are all mail-scanner processes in action during the 
smtp timeout and taking the majority of cpu resources?