Linux Iostat Performance indicator description (RPM)

Iostat belongs to the Sysstat package. Can be installed directly with Yum install Sysstat.

Note:

• If the value of%iowait is too high, it indicates that the hard disk has an I/O bottleneck
• The%idle value is high, indicating that the CPU is more idle,
• If the%idle value is high but the system responds slowly, it is possible that the CPU waits for the allocated memory, and the memory capacity should be increased at this time.
• If the%idle value continues below 10, the system's CPU processing power is relatively low, indicating that the most resource to be addressed in the system is the CPU.

Note:

• If%util is close to 100%, it indicates that there are too many I/O requests, the I/O system is full, and the disk may have bottlenecks.
• If SVCTM is closer to await, I/O has almost no waiting time;
• If the await is much larger than SVCTM, stating that the I/O queue is too long and the IO response is too slow, the necessary optimizations need to be made.
• If the Avgqu-sz is larger, it also indicates that there is an equivalent IO waiting.

• The size of an await typically depends on the service time (SVCTM) and the length of the I/O queue and the emit mode of the I/O request. Generally SVCTM < await, because the waiting time for waiting requests is repeatedly computed. If SVCTM is closer to await, I/O has little waiting time

Common commands: Iostat 1 4/DEV/SDB-XMD

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Linux Iostat Performance indicator description (RPM)