[geeks] thoughts on SMTP

[Scott Howard]

On Sun, Mar 24, 2002 at 12:10:40AM -0500, Greg A. Woods wrote:
> Unless you're running one of the 0.01% of mail servers that actually use
> as much CPU as they can I'll bet dollars to donuts that you've got more
> than enough CPU to compress and decompress every SMTP stream you accept
> or create.

Anyone who runs a mail server which handles any volume of mail will
be running a mail server which is relatively busy, and without getting
these servers running compression, there's no much point.  It's all
well and good to have 99% of the mail servers on the internet running
compression, but if the other 1% handle 98% of the mail, then there's
mot much point...

One of our two (load balancing) external mail servers for Friday :

00:00:00    %usr    %sys    %wio   %idle
09:00:02      33      20       2      45
09:10:01      22      17       2      58
09:20:00      28      22       3      48
09:30:01      30      26       3      41
09:40:00      33      27       2      38
09:50:01      28      18       2      51
10:00:00      28      16       2      54
10:10:00      16      14       3      68
10:20:00      21      22       5      53
10:30:01      39      28       3      30
10:40:01      55      44       0       1
10:50:00      38      28       2      31

(2x Ultra 1-170's, 512Mb memory, moving a few gigs of mail _each_ per days)

> Modern mail Unix servers are always I/O bound -- never CPU bound.

For a small shop perhaps... not for anyone running a reasonable sized mail
server.

  Scott.