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--- aix:aix_crontab [2024/01/11 09:45]
manu created
+++ aix:aix_crontab [2025/04/29 15:59] (current)
manu
@@ Line 7: / Line 7: @@
 Add crontab
 <cli prompt='#'>
-echo '* * * * * /usr/bin/perl /opt/lpar2rrd-agent/lpar2rrd-agent.pl lnxmonitor01 > /var/tmp/lpar2rrd-agent1.out 2>&1' > /tmp/cron_lpar2rrd
+[root@aixna001]/root# echo '* * * * * /usr/bin/perl /opt/lpar2rrd-agent/lpar2rrd-agent.pl lnxmonitor01 > /var/tmp/lpar2rrd-agent1.out 2>&1' > /tmp/cron_lpar2rrd
-su - lpar2rrd -c 'crontab  /tmp/cron_lpar2rrd'
+[root@aixna001]/root# su - lpar2rrd -c 'crontab  /tmp/cron_lpar2rrd'
 </cli>
 ===== Check crontab =====
+List crontab for a user
 <cli prompt='>'>
 [root@aixna001]/root> crontab -l lpar2rrd
 1 * * * /usr/bin/perl /opt/lpar2rrd-agent/lpar2rrd-agent.pl lnxmonitor01 > /var/tmp/lpar2rrd-agent.out 2>&1
+18 * * 1,2,3,4,5 ( . /home/lpar/.bash_profile ; /myscript/script01.sh ) >/dev/null 2>&1
+</cli>
+Check latest appied crontab
+<cli prompt='>'>
 [root@aixna001]/root> crontab -v lpar2rrd
 Crontab file: lpar2rrd     Submission time: Thu Jan 11 09:32:45 CET 2024
 </cli>
+Fields description
+  * minute:          0 through 59
+  * hour:            0 through 23
+  * day_of_month:    1 through 31
+  * month:           1 through 12
+  * weekday:         0 through 6 for Sunday through Saturday
+FIXME
+On linux (NOT AIX) you can also use for very 10 minutes, */10
+,10,20,30,40,50 6 * * 1-5 /usr/bin/calendar
+   */10 * * 1-5 /usr/bin/calendar
+==== Cron log ====
+Default log output is located in**/var/adm/cron/log**
+You can use logrotate mechanism to rotate this log, or choose the following steps
+=== Crontab and log management ===
+By default on AIX cron process use the file **/etc/cronlog.conf** to customize cronlog.\\
+In this file you can easily rotate cron logfile.
+To log information in directory /var/cronjobs, log file cron.out, size of 50k, total number of rotated files = 4, archive in /var/cronarch, archive files with compression, create the configuration file as follows:
+<cli prompt='>'>
+[root@aix001] /root> cat  /etc/cronlog.conf
+...
+logfile=/var/cronjobs/cron.out
+  size=50K
+  rotate=4
+  archive=/var/cronarch
+  compress
+</cli>
+==== Errors ====
+I found that the log is located in **/var/adm/log**. Further we are getting this error repeatedly ever since this date/time. How do I clear this max limit?
+  c queue max run limit reached Fri Nov 25 21:52:00 2016
+  ! rescheduling a cron job Fri Nov 25 21:52:00 2016
+The cron daemon has a limit of how many jobs it can run simultaneously. By default it is 100 jobs. If a new job is scheduled to run, and the limit has already been reached, the job will be rescheduled at a later time (the default is 60 seconds later). Both the number of jobs and wait time are configured in the file **/var/adm/cron/queuedefs**.
+To do this, add an entry to the bottom of the /var/adm/cron/queuedefs file using an editor such as vi. The entry should have the form:
+  c.50j20n60w
+where
+  * c. = The "c" or cron queue, followed by a period separator.
+  * Nj = The maximum number of jobs to be run simultaneously by cron, followed by the letter "j".
+  * Nn = The "nice" value of the jobs to be run (default is 2), followed by the letter "n".
+  * Nw = The time a job has to wait until the next attempt to run it, followed by the letter "w".
+For example:
+  This example would set the cron queue to a maximum of 200 jobs, with a nice value of 2, and a wait time of 60 seconds.
+<cli prompt='#'>
+root@orathal-test /var/tmp# cat /var/adm/cron/queuedefs
+c.200j2n60w
+</cli>
+c.200j2n60w

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