Note: This is an RHCE 7 exam objective.
Install the sysstat package if it’s not already the case:
# yum install -y sysstat
Activate the sysstat service at boot (if it’s not already the case):
# systemctl enable sysstat
Produce a report for a given day (here the 11th) (-u for CPU usage, -r for memory usage, -dp for disk activity, -n DEV for network activity):
# sadf -d /var/log/sa/sa11 -- -u -r -dp -n DEV
Performance analysis starts with the top command that displays the current activity (CPU, memory) on a server.
glances, available through the EPEL repository, is a less known command that displays even more information than top (network usage, disk I/O, filesystem usage).
This spits out a very large wall of text, that’s all that’s required?
A question like, “Identify at what times CPU utilization peaks” or similar, I wouldn’t be able to answer.
Maybe a little bit more of the background will be better for overall understanding.
So in the essence, once sar utility is present on the system by installing sysstat package, cron job will be created under /etc/cron.d/sysstat
This cron job will collect data about the system every 10 minutes and put the data into /var/log/sa , sar command will use this data to generate the reports, meaning if cron job didn’t kick and collected data, you will not be able to produce any report. Another tunable is stored at /etc/sysconfig/sysstat – here we can change retention, meaning for how long will sar keep the data.
Has anyone ever known this objective appeared in real EX300?
I don’t think so.
Never taken the exam, but my guess is that the “deliver reports” part just means redirecting stdout of the sadf command to a file. >>