[Mimedefang] Performance Tuning

[Robert Covell]

What are the best settings for tuning a setup that has fairly heavy traffic.
Several times throughout the day our relay server notifies us of very high
cpu usage.  We have tried to tweak the setup, which has gotten better, but
it still runs very high at times.

Setup:
AMD Athlon(tm) XP 1700+
265MB Ram
sendmail-8.12.5
mimedefang-2.16 using the multiplexor
Mail-SpamAssassin-2.20

mimedefang-ctrl Setup:

#!/bin/sh
#
# Generic start/stop script for MIMEDefang.  Should work on most
# flavors of UNIX.

RETVAL=0
prog='mimedefang'
SPOOLDIR='/var/spool/MIMEDefang'
PID="$SPOOLDIR/$prog.pid"
MXPID="$SPOOLDIR/$prog-multiplexor.pid"

# Is the program executable?  We search in /usr/bin and /usr/local/bin.

if [ -x /usr/local/bin/$prog ] ; then
    PROGDIR=/usr/local/bin
elif [ -x /usr/bin/$prog ] ; then
    PROGDIR=/usr/bin
elif [ -x /usr/local/bin/$prog ] ; then
    PROGDIR=/usr/local/bin
else
    exit 0
fi

# The settings which follow are defaults.  You can override them by
# placing assignments in /etc/mail/mimedefang.conf

# The socket used by mimedefang to communicate with sendmail
# SOCKET=$SPOOLDIR/mimedefang.sock
SOCKET=/var/run/mimedefang.sock

# Maximum number of processes to run (mail received while this many
# processes are running is rejected with a temporary failure, so be
# wary of how many emails you receive at a time).  This applies only
# if you do NOT use the multiplexor
# MAXIMUM=10

# If you want the multiplexor, you need to uncomment this line
MULTIPLEXOR=yes

# Run the multiplexor and filters as this user, not root.  RECOMMENDED
# MX_USER=defang

# If you want to keep spool directories around if the filter fails,
# set the next one to yes
# KEEP_FAILED_DIRECTORIES=no

# The following apply only to the multiplexor and are used only when
# the MULTIPLEXOR variable is 'yes'

# "yes" turns on the multiplexor relay checking function
# MX_RELAY_CHECK=no

# "yes" turns on the multiplexor sender checking function
# MX_SENDER_CHECK=no

# "yes" turns on the multiplexor recipient checking function
# MX_RECIPIENT_CHECK=no

# Set to yes if you want the multiplexor to log events to syslog
MX_LOG=yes

# The multiplexor does not start all slaves at the same time.  Instead,
# it starts one slave every MX_SLAVE_DELAY seconds when the system is idle.
# (If the system is busy, the multiplexor starts slaves as incoming mail
# requires attention.)
MX_SLAVE_DELAY=3

# The next setting is an absolute limit on slave activation.  The
multiplexor
# will NEVER activate a slave within MX_MIN_SLAVE_DELAY seconds of another.
# The default of zero means that the multiplexor will activate slaves as
# quickly as necessary to keep up with incoming mail.
# MX_MIN_SLAVE_DELAY=0

# Set to yes if you want the multiplexor to log stats in
# /var/log/mimedefang/stats
# MX_STATS=no

# Set to yes if you want the stats file flushed after each entry
# MX_FLUSH_STATS=no

# Set to yes if you want the multiplexor to log stats to syslog
# MX_STATS_SYSLOG=no

# The socket used by the multiplexor
MX_SOCKET=$SPOOLDIR/mimedefang-multiplexor.sock

# Maximum # of requests a process handles
MX_REQUESTS=100

# Minimum number of processes to keep.  The default of 0 is probably
# too low; we suggest 2 instead.
MX_MINIMUM=4

# Maximum number of processes to run (mail received while this many
# processes are running is rejected with a temporary failure, so be
# wary of how many emails you receive at a time).  This applies only
# if you DO use the multiplexor.  The default value of 2 is probably
# too low; we suggest 10 instead
MX_MAXIMUM=20

# Limit slave processes' resident-set size to this many kilobytes.  Default
# is unlimited.
# MX_MAX_RSS=10000

# Limit total size of slave processes' memory space to this many kilobytes.
# Default is unlimited.
# MX_MAX_AS=30000

# Number of seconds a process should be idle before checking for
# minimum number and killed
MX_IDLE=300

# Number of seconds a process is allowed to scan an email before it is
# considered dead.  The default is 30 seconds; we suggest 300.
MX_BUSY=300


Sincerely,

Robert T. Covell
President / Owner
Rolet Internet Services, LLC
Web: www.rolet.com
Email: rcovell at rolet.com
Phone: 816.471.1095
Fax: 816.471.3447
24x7: 816.210.7145