Collect, Save and Report Linux System Activity Information
SAR
The SAR command reports content of selected activity counters in the Linux System which are collected using sysstat over a period of time. You can select information about specific system activities using flags.The data can be redirected to an outfile which can be interrogated later.
Are you using a large SQL query and at the same time running your backup? Well we can report on the performance using the below commands.
CPU & Disk Performance:
We can run the below command to report on our CPU utilisation every 10 minutes.
[root@server ~]# sar -u
01:30:01 PM CPU %user %nice %system %iowait %steal %idle
01:40:01 PM all 0.11 0.00 0.09 0.00 0.02 99.78
01:50:02 PM all 0.10 0.00 0.09 0.00 0.02 99.79
Average: all 0.11 0.00 0.09 0.00 0.02 99.7801:51:22 PM LINUX RESTART02:00:01 PM CPU %user %nice %system %iowait %steal %idle
02:10:01 PM all 0.12 0.00 0.10 0.00 0.02 99.77
02:20:01 PM all 0.11 0.00 0.09 0.00 0.02 99.78
02:30:01 PM all 0.12 0.00 0.11 0.04 0.02 99.72
02:40:01 PM all 0.12 0.00 0.09 0.00 0.02 99.77
Average: all 0.12 0.00 0.09 0.01 0.02 99.76
We can also use the -b flag to report on disk utilisation.
Report on Network Activity
Do you want to see statistics from your network devices? For e.g. lets report data on our network interface cards. I only have one NIC on my Centos 7.
[root@server~]# sar -n DEV
01:30:01 PM IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s txcmp/s
01:40:01 PM ens5 1.96 2.00 0.46 0.35 0.00 0.00
01:40:01 PM lo 0.00 0.00 0.00 0.00 0.00 0.00
01:50:02 PM ens5 1.93 1.96 0.45 0.35 0.00 0.00 How about printing data for a specific time period?
Lets filter the output based on timestamp and also pull up information from a particular log file by adding the file name as an argument to the sar command.
[root@server~]# sar -s 14:00:00 -e 15:00:00 /var/log/sa/sa15