View disk read/write status in centos

When the system slows down, we may first focus on the cpu metrics. Sometimes we find that the cpu usage is not high at all, but the system is still stuck, in this case, you may need to consider another thing that affects performance-the disk's IO performance. You can use % wa in the top command to obtain the current io status of the system. If the value remains high, the disk IO may be faulty. In addition, you can use the iotop command to learn more about the program's disk reading and writing speed, command line, pid, and other information. If this command does not exist, run the following command to install it:

Yum-y install iotop

In addition, you can use the dd command to test the disk write performance. For example:

Dd if =/dev/zero of = test bs = 64 k count = 4 k oflag = dsync

After the command is executed, the average speed of disk write operations is displayed.