Addrsperjob, filesperjob Channel Options

Number of message files or addresses to handle per service job or file
The MTA normally creates one delivery service job per channel that needs service. This applies to both immediate service and periodic service jobs: when a message is initially sent and immediate service is needed one job is created for each channel to which the message is queued, and when the MTA creates periodic jobs it normally creates one periodic job for each channel that needs service.

A single service job may not be sufficient to insure prompt delivery of all messages, however.

The  and   channel options can be used to cause the MTA to create additional service jobs. Each one of these options takes a single positive integer parameter which specifies how many addresses or queue entries (i.e., files) must be sent to the associated channel before more than one service job is created to handle them. If a value less than or equal to zero is given it is interpreted as a request to queue only one service job. Not specifying an option is equivalent to specifying a value of zero. The effect of these options is maximized; the larger number computed will be the number of service jobs that are actually created.

The  channel option computes the number of services jobs to start by dividing the total number of To: addressees in all entries by the given value. The  channel option divides the number of actual queue entries or files by the given value. Note that the number of queue entries resulting from a given message is controlled by a large number of factors, including but not limited to the use of the   and    channel options and the specification of header-modifying actions in mailing lists. Also note that the  channel option places an upper bound on the total number of service jobs that can be created.

For example, if a message with 4 recipient addresses is queued to a channel marked  and   a total of 2 service jobs will be created. But if a message with 23 recipient addresses is queued to the same channel only 5 jobs will be created because of the   restriction.

Note that these channel options affect the creation of both periodic and immediate service jobs. In the case of periodic jobs the number of jobs created is calculated from the total number of messages in the channel queue. In the case of immediate service jobs the calculation is based only on the message being entered into the queue at the time.

Finally, note that the  option is generally only useful on channels that provide per-address service granularity. Currently this is limited to PMDF-FAX channels; there is no case where it is useful for the Messaging Server.

See also:
 * single Option
 * single_sys Option
 * maxjobs Option
 * Channel options