queuedefs — Queue description for at, batch, and cron
Related information
Description
q . [njobj] [nicen] [nwaitw]
- q
- Specifies the name of the queue. Jobs started by at default to queue a; jobs started by batch default to queue b, and crontab files default to queue c. Queue names can be any single-byte character except a space, tab, newline, null, or number sign (#).
- njob
- Specifies the maximum number of jobs that can be run in the queue simultaneously. If more than njob jobs are ready to run, cron runs the first njob jobs immediately, and runs the others as current jobs terminate. The default value is 100.
- nice
- Specifies the nice value (see nice) that cron assigns to all jobs in the queue that are not run by a user ID with appropriate privileges. The default value is 2.
- nwait
- Specifies the number of seconds that cron is to wait before it reschedules a job that was deferred because there were more than njob jobs running in that job's queue, or because more than 25 jobs were running in all queues. The default value is 60.
Lines beginning with a number sign (#) are comments, and are ignored.
Examples
#
# Sample queuedefs file
#
a.5j3n
b.3j1n90w
This file indicates that the a queue, for at jobs, can have a maximum of five jobs running simultaneously. crontab runs the jobs with a nice value of 3. Because there is no nwait field for this queue, if cron cannot run a job because too many other jobs are running, it waits 60 seconds before trying to run it again.
This file also states that the b queue, for batch jobs, can have a maximum of three jobs running simultaneously. cron runs the jobs with a nice value of 1. If cron cannot run a job because too many other jobs are running, it waits 90 seconds before trying to run it again. All other queues can run up to 100 jobs simultaneously; cron runs these jobs with a nice value of 2 and, if it cannot run a job because too many other jobs are running, it waits 60 seconds before trying to run it again.
Related information
The at, batch, and crontab commands.