When the load average on a machine (the average number of processes in the queue run over the last minute) becomes too high, sendmail can compensate in three different ways:

• This QueueLA option determines the load at which sendmail will begin to queue messages rather than delivering them, and the load at which scheduled runs will be skipped.

• The RefuseLA option (RefuseLA) determines the load at which sendmail will begin to refuse connections rather than accepting them.

• The DelayLA option (DelayLA) determines the load at which sendmail will begin to delay replies to SMTP commands.

The QueueLA option specifies the load above which sendmail queues messages rather than delivering them. The QueueLA and QueueFactor options interact to determine this cutoff; they are both covered under the QueueFactor option (QueueFactor).

The forms of the QueueLA option are as follows:

O QueueLA=load             configuration file (V8.7 and later) 
-OQueueLA=load             command line (V8.7 and later) 
define(`confQUEUE_LA',load)    mc configuration (V8.7 and later) 
Oxload                     configuration file (deprecated) 
-oxload                    command line (deprecated) 

The optional argument load, of type numeric, defaults to zero if it is missing. If the entire QueueLA option is missing, the default value given to load is eight times the number of CPU processors. The default for the mc technique is to omit this option. On newer, faster machines a higher setting might be more appropriate.

This QueueLA option is effective only if your sendmail binary was compiled with load-average support (LA_TYPE). You can use the -d3.1 debugging switch to discover whether your binary includes the necessary support.

The QueueLA option is not safe. If specified from the command line, it can cause sendmail to relinquish its root privilege.