can be asked to queue (but not deliver)
mail if the system load average gets too high
using the QueueLA (x) option.
When the load average exceeds the value of the
QueueLA option, the delivery mode is set to
q (queue only) if the QueueFactor
divided by the difference in the current load average and the
QueueLA option plus one
exceeds the priority of the message--that is,
the message is queued if:
pri > QueueFactor divided by (LA-QueueLA+1)
The QueueFactor option defaults to 600,000, so each point of load average is worth 600,000 priority points (as described above).
For drastic cases, the RefuseLA (X) option defines a load average at which sendmail will refuse to accept network connections. Locally generated mail (including incoming UUCP mail) is still accepted.