![]() ![]() It's homepage is at .Īlternatives See Comparison Of System Monitoring Programs. Using the sar command, you can monitor the CPU usage at a certain interval as. ![]() The sar manual page is very long and it may be worth a look. Check CPU usage Utilization on Linux with top command Top is a basic Linux. sar can tell you if the box is or was low on memory, if it's network was at capacity, if it is doing too much slow I/O and so on. Other tools like vmstat and iostat can get some of the same real-time information but they can't tell you what happened yesterday or a day last week. Sar can be very useful if you would like to know why a box serving some service is or was slow or unresponsive. sar -u 3600 20 -f /var/log/sa/sa04 will output 20 lines of CPU use snapshots from the top of the hour on the 4th day of the month.That list may be long since no number of lines is specified. sar -u -f /var/log/sa/sa04 will output CPU usage snapshots at the interval they were recorded using the log file for the 4th of the month.sar -u will output the last available historical information.sar -u 1 10 will output ten lines of real-time data with 1-second snapshots.Thus we get sar -u 3600 10 -f /var/log/sa/sa08 Summary: Choosing Real-Time Or Historical Informatoin If you require a snapshot of the CPU load every hour for the first 10 hours of that day then the -u option should be used to specify that CPU data is what you want and it's option should be 3600 (60 seconds * 60 minutes = 1 hour). Sar showing a hourly CPU information snapshot from November 8th 2019 on a box with low load. ![]() 1200 would be every 20 minutes (60 seconds in a minute * 20). The above cron job saves data every 10 minutes (=600 seconds) which means that values less than that are ignored. Specifying the interval of the data is slightly more tricky. The parameters specifying what you want information about are the same as you would use for real-time data. The cron-job invokes sysstat's bundled sa - always with two digits - so a log file from the 8th would be sa08 - NOT sa8. Installing the sysstat package will either create two broken systemd files which do nothing in /usr/lib/systemd/system/ named sysstat-collect.timer and rvice or a functioning cron job depending on the GNU/Linux distribution chosen. Sar is part of the sysstat system utility package by Sebastien Godard (install sysstat to get it, there is no separate package named sar).
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