Dell PowerVault MD3260i - Manual (Page 114)

The following additional SSD cache-related commands are available in this document:
• Change SSD Cache Application Type
• Blink SSD Cache
• Rename SSD Cache
• Resume SSD Cache
• Show SSD Cache
• Suspend SSD Cache
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 functioning correctly:
1 Reads the test
2 Performs a data loop-back test
3 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.
For best results, run all three tests at initial installation. Also, run the tests any time you make changes to the storage
array or to components connected to the storage array (such as hubs, switches, and host adapters).
A custom data pattern file called diagnosticsDataPattern.dpf is included on the Utility directory of the installation CD.
You can modify this file, but the file must have the following properties to work correctly for the tests:
• The file values must be entered in hexadecimal format (00 to FF) with only one space between the values.
• The file must be no larger than 64 bytes in size. Smaller files can be used, but larger files can cause an error.
114