On RHEL8, it uses systemd instead of cron jobs to manage SAR data collection service.
Run the following command to check if the SAR data collection is started.
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[root@h04-11 ~]# cat /etc/redhat-release
Red Hat Enterprise Linux release 8.5 (Ootpa)
[root@h04-11 ~]# systemctl status sysstat-collect.timer
● sysstat-collect.timer - Run system activity accounting tool every 10 minutes
Loaded: loaded (/usr/lib/systemd/system/sysstat-collect.timer; enabled; vendor preset: disabled)
Active: inactive (dead)
Trigger: n/a
If it’s not started, run the following command to start it.
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[root@h04-11 ~]# systemctl start sysstat-collect.timer
[root@h04-11 ~]# systemctl status sysstat-collect.timer
● sysstat-collect.timer - Run system activity accounting tool every 10 minutes
Loaded: loaded (/usr/lib/systemd/system/sysstat-collect.timer; enabled; vendor preset: disabled)
Active: active (waiting) since Tue 2022-01-04 19:49:54 UTC; 1s ago
Trigger: Tue 2022-01-04 19:50:00 UTC; 4s left
Jan 04 19:49:54 h04-11 systemd[1]: Started Run system activity accounting tool every 10 minutes.
Check the sar file existence after a few minutes as below.
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[root@h04-11 ~]# ls -ltr /var/log/sa
total 0
[root@h04-11 ~]# date
Tue Jan 4 19:50:25 UTC 2022
[root@h04-11 ~]# ls -ltr /var/log/sa
total 12
-rw-r--r--. 1 root root 11632 Jan 4 19:50 sa04
Check the default interval of SAR data collection as below.
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[root@h04-11 ~]# systemctl cat sysstat-collect.timer
# /usr/lib/systemd/system/sysstat-collect.timer
# /usr/lib/systemd/system/sysstat-collect.timer
# (C) 2014 Tomasz Torcz <tomek@pipebreaker.pl>
#
# sysstat-11.7.3 systemd unit file:
# Activates activity collector every 10 minutes
[Unit]
Description=Run system activity accounting tool every 10 minutes
[Timer]
OnCalendar=*:00/10
[Install]
WantedBy=sysstat.service
To change the interval of SAR data collection, edit the systemd unit file as below.
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[root@h04-11 ~]# export SYSTEMD_EDITOR=/usr/bin/vi
[root@h04-11 ~]# systemctl edit sysstat-collect.timer
Add the following to set the desired interval. In this example, we changed it from 10 minutes to 1 minute. The blank “OnCalendar=” directive is there to remove the original setting.
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[Unit]
Description=Run system activity accounting tool every 1 minute
[Timer]
OnCalendar=
OnCalendar=*:00/1
Reload systemd service to apply the change.
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[root@h04-11 ~]# systemctl daemon-reload
[root@h04-11 ~]# systemctl cat sysstat-collect.timer
# /usr/lib/systemd/system/sysstat-collect.timer
# /usr/lib/systemd/system/sysstat-collect.timer
# (C) 2014 Tomasz Torcz <tomek@pipebreaker.pl>
#
# sysstat-11.7.3 systemd unit file:
# Activates activity collector every 10 minutes
[Unit]
Description=Run system activity accounting tool every 10 minutes
[Timer]
OnCalendar=*:00/10
[Install]
WantedBy=sysstat.service
# /etc/systemd/system/sysstat-collect.timer.d/override.conf
[Unit]
Description=Run system activity accounting tool every 1 minute
[Timer]
OnCalendar=
OnCalendar=*:00/1
[root@h04-11 ~]# cat /etc/systemd/system/sysstat-collect.timer.d/override.conf
[Unit]
Description=Run system activity accounting tool every 1 minute
[Timer]
OnCalendar=
OnCalendar=*:00/1
[root@h04-11 ~]# systemctl status sysstat-collect.timer
● sysstat-collect.timer - Run system activity accounting tool every 1 minute
Loaded: loaded (/usr/lib/systemd/system/sysstat-collect.timer; enabled; vendor preset: disabled)
Drop-In: /etc/systemd/system/sysstat-collect.timer.d
└─override.conf
Active: active (running) since Tue 2022-01-04 19:49:54 UTC; 27min ago
Trigger: n/a
Jan 04 19:49:54 h04-11 systemd[1]: Started Run system activity accounting tool every 10 minutes.
To verify if the interval of SAR data collection is modified successfully, do the following.
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[root@h04-11 ~]# sar -u -f /var/log/sa/sa04
Linux 4.18.0-348.2.1.el8_5.x86_64 (h04-11) 01/04/2022 _x86_64_ (32 CPU)
07:50:18 PM CPU %user %nice %system %iowait %steal %idle
08:00:18 PM all 0.11 0.00 0.13 0.00 0.00 99.76
08:10:08 PM all 0.11 0.00 0.13 0.00 0.00 99.75
08:14:08 PM all 0.12 0.00 0.13 0.00 0.00 99.74
08:15:35 PM all 0.12 0.00 0.13 0.01 0.00 99.73
08:16:18 PM all 0.12 0.00 0.14 0.02 0.00 99.72
08:17:07 PM all 0.10 0.00 0.13 0.00 0.00 99.77
08:18:18 PM all 0.12 0.00 0.13 0.00 0.00 99.75
Average: all 0.11 0.00 0.13 0.00 0.00 99.75
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