Detailed description of iostat commands

Detailed description of iostat commands

Iostat is used to output statistics about input and output of CPU and disk, partition, and Network File System (NFS. The iostat command is used to monitor the input/output status of system devices and generate reports to modify system configurations based on statistical reports for better performance.

Command Format:
Iostat [-c] [-d] [-N] [-n] [-h] [-k |-m] [-t] [-V] [-x] [-z] [device [...] | ALL] [-p [device [,...] | ALL] [interval [count]

Iostat can generate three types of reports: CPU utilization report, device utilization report, and Network File System utilization report.
The iostat command format is as follows:
Iostat [parameter] [time] [times]
The time is measured in seconds.

1. Simple use of the iostat command
The iostat command displays the load and partition status information of the CPU and I/O systems.
You can directly execute the iostat command to display the following content:
 
# Iostat
# Iostat-xm
(Display the extended information with xm parameters and change each sector of the disk data to display [1 sector equals 512 bytes] per mb ])

The output items are as follows:
1) avg-cpu segment:
% User: the percentage of CPU used to run at the user level.
% Nice: Percentage of CPU used by nice operations.
% System: Percentage of CPU used to run at the system level (kernel.
% Iowait: CPU usage when the CPU waits for hardware I/O.
% Steal: Percentage of unconscious waiting time of the virtual CPU when the hypervisor maintains another virtual processor.
% Idle: Percentage of idle CPU time.
 
Device segment:
Tps: the number of I/O requests per second on the device. Multiple logical requests may be merged into "one I/O Request ".
Blk_read/s: number of blocks read per second
Blk_wrtn/s: number of blocks written per second
Blk_read: Total number of read Blocks
Blk_wrtn: Total number of blocks written
Number of write requests sent to the device per second after wrqm/s merges write requests.

2. parameter description of the iostat command
-C only displays CPU statistics. It is mutually exclusive with the-d option.
-D: Only Displays disk statistics. It is mutually exclusive with the-c option.
-K displays the number of disk requests per second in KB. The default unit is block.
-MB: the number of disk requests per second is displayed in MB.
-N: Display disk array information
-N: displays the Network File System NFS report. This option applies only to Linux kernel 2.6.17 and later versions.
-P device | ALL
This parameter is mutually exclusive with the-x option. It is used to display the statistics of Block devices and system partitions. You can also specify a device name after-p, for example:
# Iostat-p hda
Or display all devices:
# Iostat-p ALL
-T print the time when data is output.
-V: print the version number and help information.
-X output extension information.

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