---iostat of Linux commands

Iostat command Explanation

The iostat is used to output CPU and disk input and output, partition, Network File system NFS-related statistics. The Iostat command monitors the input/output status of system devices and generates reports to modify the system configuration for better performance based on statistical reporting.

Command format:
Iostat [-c] [-d] [-n] [-n] [-h] [-K |-m] [-t] [-v] [-X] [-z] [device [...] | ALL] [-p [device [,...] | all] [interval [count]]

Iostat can produce three types of reports: CPU utilization reports, device utilization reports, and network File system utilization reports.
The IOSTAT command format can be summarized as:
iostat[parameters [TIME] [number]
Where the time is in seconds.

1. Simple use of iostat command
The Iostat command displays the load conditions and partition status information for the CPU and I/O systems.
Execute the iostat command directly to display the following:

# Iostat
# IOSTAT-XM
(with the XM parameter to display extended information and to change the disk data per sector to a per-megabyte display "1 sector equals 512 bytes")

The meanings of the various output items are as follows:
1) avg-cpu section:
%user: The percentage of CPU that is used to run at the user level.
The percentage of CPU used by the%nice:nice operation.
%system: The percentage of CPU that is used to run at the system level (kernel).
%iowait:cpu the percentage of CPU that is consumed while waiting for hardware I/O.
%steal: The percentage of the virtual CPU's unconscious wait time when the hypervisor maintains another virtualized processor.
%idle:cpu the percentage of idle time.

Device segment:
TPS: The number of I/O requests per second for the device, and 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 block writes per second
Blk_read: Total block Read-in
Blk_wrtn: Number of block writes
wrqm/s the number of write requests sent to the device per second after the write request is merged.

2. Parameter description of Iostat command
-C displays only CPU statistics. Mutually exclusive with the-D option.
-D displays only disk statistics. Mutually exclusive with-c option.
-K Displays the number of disk requests per second in kilobytes, the default unit block.
-M displays the number of disk requests per second in megabytes.
-N Display disk array information
-N Displays the Network File System NFS report. This option is only available for Linux kernel 2.6.17 or later.
-P Device | All
Mutually exclusive with the-X option to display statistics for block devices and system partitions, or to specify a device name after-p, such as:
# iostat-p HDA
Or Show All devices:
# iostat-p All
-T prints the time to collect data when the data is output.
-V Prints the version number and help information.
-X Output extension information.

---of the linux command Iostat