HP-UX Mailing Services Administrator's Guide

Mailing Services Overview
The Sendmail Utility
Chapter 134
in temporary failures, but the attempt to connect to munch fails
permanently, the message is returned as an error. If the attempts to
connect to bling and wheo result in permanent failures, but the
attempt to connect to munch fails temporarily, the message is queued.
• A host cannot deliver a message to another host for which it is a mail
exchanger.
This failure is handled as a normal delivery failure, either by the
mail exchanger host or by the host sending to the mail exchanger.
How Sendmail Improves Mail Queue Performance
Mail queue performance is impacted by the number of entries in the
queue directories. Multiple Queue Directories improves mail queue
performance in Sendmail. This feature facilitates the parallel processing
of mail by spreading process loads across multiple disks, thereby
improving the queue performance. UNIX files take a long time to open
when entries in the directories exceed 100.
In order to use multiple directories, you must supply the
QueueDirectory option in the sendmail.cf file with a value ending
with *.
For example, if you specify the following in the configuration file, all the
directories or links to directories that begin with g will be used:
O QueueDirectory=/var/spool/mqueue/g*
If there are five directories, g1, g2, g3, g4, and g5, Sendmail uses all five
directories when the Sendmail daemon is restarted. Mail is randomly
assigned to the queue directories. Do not change the queue directory
structure when Sendmail is running.
You can flush individual mail queues by specifying the following on the
command line:
sendmail -q -O QueueDirectory=/var/spool/mqueue/g1
sendmail -q -O QueueDirectory=/var/spool/mqueue/g3
You can use the mailq command to display the mail queue, as shown in
the following example:
#mailq
/var/spool/mqueue/g1 is empty
/var/spool/mqueue/g2 (1 request)
--Q-ID--- -Size- --Q-Time-- ----------Sender/Recipient--