The Diagnostics option lets you verify that a is functioning correctly, through the use of various internal tests.
Important:
During the diagnostics, the controller on which the tests are run is not available for I/O.The diagnostics use a combination of three different tests: read test, write test, and data loopback test. You should run all three tests at initial installation and at any time there are changes to the or the components that are connected to the storage subsystem, such as hubs, switches, and.
The read test initiates a read command as it would be sent over an I/O data path. The read test compares data with a known, specific data pattern, and the test checks for data integrity and errors. If the read command is unsuccessful or the data compared is not correct, the test considers that the controller is in error. The test fails the controller.
A write test initiates a write command as it would be sent over an I/O data path to the diagnostics region on a specified disk drive. This diagnostics region is then read and compared to a specific data pattern. If the write fails or the data compared is not correct, the test fails the controller and places the controller offline. Use the Recovery Guru to replace the controller.
Important:
The data loopback test does not run on controllers that have SCSI connections between the controllers and the disk drives.The data loopback test is run only on controllers that have connections between the controller and the disk drives. The test passes data through the disk drive-side channel, minihub on each controller, out onto the loop, and then back again. Enough data is transferred to determine error conditions on the channel. If the test fails on any channel, this status is saved so that it can be returned if all other tests pass.