Maintaining a Storage Array 123
Troubleshooting and Diagnostics
If a storage array exhibits abnormal operation or failures, you can use the
commands described in this section to determine the cause of the problems.
Collecting Physical Disk Data
To gather information about all the physical disks in a storage array, run the
save allPhysicalDisks command. This command collects sense data from all
the physical disks in a storage array and saves the data to a file. The sense data
consists of statistical information maintained by each of the physical disks in
the storage array.
Diagnosing a RAID Controller Module
The diagnose controller command’s testID parameter takes the following
options, which you can use to verify that a RAID controller module is
— Reads the test
— Performs a data loop-back test
— Writes the test
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,
checking for data integrity and errors. If the read command is unsuccessful or
the data compared is not correct, the RAID controller module is considered to
be in error and is placed offline.
Run the data loopback test only on RAID controller modules that have
connections between the RAID controller module and the physical disks. The
test passes data through each RAID controller module physical disk-side
channel out onto the loop and 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.
The write test initiates a write command as it would be sent over an I/O data
path to the diagnostics region on a specified physical disk. 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 RAID controller module is considered
to be in error, and it is failed and placed offline.
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