Linux iostat Command Detailed

The IOSTAT is an abbreviation for I/O statistics (input/output statistics), and the Iostat tool monitors the system's disk operation activity. It is characterized by the reporting of disk activity statistics, as well as the reporting of CPU usage. Iostat also has a weakness, that is, it can not analyze a process in depth, only the overall situation of the system to analyze

Common Command Display

Iostat Installation

# Iostat belongs to the Sysstat package. can be installed directly.

Show all device load conditions

Iostat

Description

Description of the CPU attribute value:

%user:cpu the percentage of time in user mode.

%nice:cpu the percentage of time in user mode with nice value.

%system:cpu the percentage of time in system mode.

%iowait:cpu the percentage of time to wait for the input output to finish.

%steal: The percentage of the virtual CPU's unconscious wait time when the hypervisor maintains another virtualized processor.

%IDLE:CPU idle time percentage.

Note:

If the%iowait value is too high, the hard disk has an I/O bottleneck

If the%idle value is high, the CPU is more idle

If the%idle value is high but the system responds slowly, the CPU may be waiting to allocate memory and should increase its memory capacity.

If the%idle value continues below 10, the CPU processing power is relatively low, and the resource most needed to resolve in the system is the CPU.

Description of the CPU attribute value:

TPS: Number of transmissions per second for this device

KB_READ/S: The amount of data read from the device (drive expressed) per second;

KB_WRTN/S: The amount of data written to the device (drive expressed) per second;

Kb_read: The total amount of data read;

KB_WRTN: The total amount of data written;

Show all information at timed intervals

# "Refresh the display every 2 seconds and display 3 times" Iostat 2  

Display specified disk information

Iostat-d/DEV/SDA

Displaying TTY and CPU information

Iostat-t

Display all information in M

Iostat-m

Viewing device usage (%util), Response time (await)

#  "-D display disk usage,-X Show Details" #  d:detailiostat-d-x-k 1 1

Description

RRQM/S: The number of read operations per second for the merge. That is Delta (rmerge)/s

WRQM/S: The number of write operations per second for the merge. That is, Delta (wmerge)/s

%util: How much time in a second is spent on I/O

If%util is close to 100%, it indicates that there are too many I/O requests and the I/O system is fully loaded

Idle less than 70% io pressure is larger, the general reading speed has more wait.

View CPU Status

Iostat-c 1 1

Linux iostat Command Detailed