sendmail, 4th Edition

QueueFactor

Factor for high-load queuing All versions

When the load average on a machine (the average number of processes in the run queue over the past minute) becomes too high, sendmail can try to compensate by queuing all mail rather than delivering it. The QueueFactor option is used in combination with the QueueLA option (QueueLA on page 1072) to calculate the point at which sendmail stops delivering. If the current load average is greater than or equal to the value given to the QueueLA option, the following formula is evaluated:

msgpri > q / (la − x + 1)

Here, q is the value set by this option, la is the current load average, and x is the cutoff load specified by the QueueLA option. If the value yielded by this calculation is less than or equal to the priority of the current mail message (msgpri in this example), the message is queued rather than delivered. Priorities are initialized with the P sendmail.cf command (Precedence on page 1148) and tuned with the RecipientFactor and ClassFactor options (RecipientFactor on page 1077). As the load average (la) grows, the value to the right of the > becomes smaller, increasing the chance that msgpri will exceed that threshold (so that the mail will be queued).

The forms of the QueueFactor option are as follows:

O QueueFactor=fact                ← configuration file (V8.7 and later)
-OQueueFactor=fact                ← command line (V8.7 and later)
define(`confQUEUE_FACTOR',fact)   ← mc configuration (V8.7 and later)
Oqfact                            ← configuration file (deprecated)
-oqfact                           ←