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C.1 iostat Command


C.1 iostat Command
The iostat command is used to regularly report the CPU usage status, as well as the terminal status, the drive status, and the I/O status.
Table C-1 lists the options of the iostat command and how those options can be applied to solving system issues.
Table C-1  iostat command options
Option Description Application
No options Reports the status of the local I/O device. Allows you to view the device status concisely in 3 lines.
-c
Reports, as ratios, the length of time that the system has been in user mode, in system mode, waiting for I/O, and idling. Allows you to view the CPU status as a concise report.
-e
Displays a summary of statistics on device errors. The displayed items are the total number of errors, hardware errors, software errors, and transfer errors. Allows you to view the accumulated number of errors as a concise table and to identify potentially failed I/O devices.
-E
Displays statistics on all the device errors. Allows you to view device information (manufacturer, model number, serial number, size, and errors).
-n
Displays the names in a descriptive form. Allows you to identify devices with a descriptive display.
-x
Reports the extended drive statistics of individual drives. Statistics are displayed in a table format.
Similar to the -e option, but differs in that it provides rate information.
Allows you to find internal devices and other I/O devices on the network whose performance is low.
The following example shows the output from the iostat command.
# iostat -En
c5t50000393D85129FAd0 Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: TOSHIBA  Product: MBF2300RC        Revision: 3706 Serial No: EB25PC201AL6
Size: 300.00GB <300000000000 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 0 Predictive Failure Analysis: 0
c3t50000393D851FDAAd0 Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: TOSHIBA  Product: MBF2300RC        Revision: 3706 Serial No: EB25PC201AMS
Size: 300.00GB <300000000000 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 0 Predictive Failure Analysis: 0
c4t50000393D822D2B6d0 Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: TOSHIBA  Product: MBF2300RC        Revision: 3706 Serial No: EB25PC2015P8
Size: 300.00GB <300000000000 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 0 Predictive Failure Analysis: 0
c2t50000393E8001BB6d0 Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: TOSHIBA  Product: MBF2300RC        Revision: 3706 Serial No: EB25PC301AV6
Size: 300.00GB <300000000000 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 0 Predictive Failure Analysis: 0
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