Silicon Graphics InfiniteStorage 4000 Series, Настройка и обслуживание, Страница: 206 / 276

194 Troubleshooting and Diagnostics
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 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 controller is considered to be in error, and it is failed and placed offline.
Run the data-loopback test only on controllers that have connections between the
controller and the drives. The test passes data through each controller drive-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 of the other tests pass.
For best results, run all three tests after you first install the storage array and any time
that you that have made changes to the storage array or the components that are
connected to the storage array (such as hubs, switches, and host adapters).
A custom data pattern file called
diagnosticsDataPattern.dpf
is included
in the root directory of the installation CD. You can modify this file, but the file must
have these 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 will work, but larger
files can cause an error.
The test results contain a generic, overall status message and a set of specific test
results. Each test result contains these items:

Test (read, write, or data loopback)

Port (read or write)

Level (internal or external)

Status (pass or fail)
Events are written to the Event Log when the diagnostics are started and when testing
is completed. These events help you to evaluate whether diagnostics testing was
successful or failed and the reason for the failure.
Running Read Link
Status Diagnostics
Read link status (RLS) error counts refer to link errors that have been detected in the
traffic flow of a Fibre Channel loop. The errors detected are represented as a count
(32-bit field) of error occurrences that are accumulated over time. The counts provide
coarse measure of the integrity of the components and devices on the loop. By
analyzing the error counts that are retrieved, you can determine the components or
devices within the Fibre Channel loop that might be experiencing problems
communicating with the other devices on the loop. A high error count for a particular
component or device indicates that it might be experiencing problems and should be
given immediate attention.