HostOnNet Blog

Server Load

When your server is under load, you need to identify the bottleneck. This can be CPU, Memory or Disk IO. Here are some of the useful commands that help you identify cause of high server load.

uptime

uptime is the first command you use to check the server load.

boby@hon-pc-01:~$ uptime
 22:50:05 up  2:02,  1 user,  load average: 0.97, 1.01, 1.00
boby@hon-pc-01:~$ 

What you need to look is load average values. This is load in last 5, 10 and 15 minutes respectively.

top

top is 2nd most used command to identify load. top give you much more details, what process running, how much CPU usage, IO usage etc..

There are alternative for top commands that provide more features like htop and atop.

vmstat

vmstat provide details about processes, memory, paging, block input/output, interrupts, and CPU activity. You can run it with command

vmstat 1

sar

sar can be used to record and analyse server load. To install sar, run

yum install sysstat

Posted in Linux