Optimizing Sendmail
Most of them involve changing the daemon’s configuration in /etc/sendmail.mc and rebuilding sendmail.cf
Specific things that can affect performance:
dnl # Sendmail, Chap 24.9.13, Page 955
dnl # Disable re-write of queue control file (will result in duplicates
dnl # if the daemon is interrupted during a delivery)
define(`confCHECKPOINTINTERVAL’,`0′)dnl
dnl # Sendmail, Chap 24.9.21, Page 960
dnl # Disable throttling the acceptance of new connections
define(`confCONNECTION_RATE_THROTTLE’,`0′)dnl
dnl # Sendmail, Chap 24.9.25, Page 967
dnl # Specify the maximum size, in bytes, of buffered df* files (default is
dnl # 4096 bytes; 0 turns this off and is not recommended)
define(`confDF_BUFFER_SIZE’,`16384′)dnl
dnl # Sendmail, Chap 24.9.60, Page 1011
dnl # Disable limit on the daemon spawning new children
define(`confMAX_DAEMON_CHILDREN’,`0′)dnl
dnl # Sendmail, Chap 24.9.66, Page 1016
dnl # Disbale limit on the number of messages that may be processed
dnl # during any one queue run
define(`confMAX_QUEUE_RUN_SIZE’,`0′)dnl
dnl # Sendmail, Chap 24.9.19, Page 959
dnl # Turn on connection caching and set maximum number of simultaneous
dnl # outbound connections kept open to 4; default is 2; this option also
dnl # depends on MCI_CACHE_TIMEOUT (below)
define(`confMCI_CACHE_SIZE’,`4′)dnl
dnl # Sendmail, Chap 24.9.19, Page 959
dnl # Set time limit on how long a cached outbound connection may be
dnl # kept open to 120 seconds (2 minutes) – see MCI_CACHE_SIZE above
define(`confMCI_CACHE_TIMEOUT’,`120s’)dnl
dnl # Sendmail, Chap 24.9.72, Page 1022
dnl # Disable time delay for queued messages not delivered on the first try
define(`confMIN_QUEUE_AGE’,`0′)dnl
dnl # Sendmail, Chapter 24.9.107, Page 1057
dnl # Disable MTA setting that forces MTA to queue each message and to sync
dnl # to disk before forking (a system crash may result in lost mail)
define(`confSAFE_QUEUE’,`false’)dnl
dnl # Sendmail, Chap 24.9.109.13, Page 1065
dnl # Disable IDENT (RFC 1413) calls/turn off sending user-host verification
define(`confTO_IDENT’,`0′)dnl
dnl # Sendmail, Chap 24.9.120, Page 1077
dnl # Specify the maximum size, in bytes, of buffered xf* files (default is
dnl # 4096 bytes; 0 turns this off and is not recommended)
define(`confXF_BUFFER_SIZE’,`16384′)dnl
dnl # Sendmail, Chap 4.8.28, Page 192
dnl # Turn off E-Mail canonization (should be done by MSA, and this
dnl # is a mail relay with no local users)
FEATURE(`nocanonify’)dnl
I’m assuming you’re using a modern version of sendmail – v8.12.10 or later. These settings may be different, or not exist at all, for older versions.
Posted on December 9th, 2009 by Denie
Filed under: Linux, Sendmail, tips
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