Read Link Status error counts refer to link errors that have been detected in the traffic flow of a
Important: Use this option only under the guidance of a Customer and Technical Support representative.
For quick access to information about a particular area, click one of the following links:
The Read Link Status Diagnostics dialog retrieves the error counts and displays the
By analyzing the error counts retrieved, it is possible to determine the components or storage arrays within the Fibre Channel loop that might be experiencing problems communicating with the other storage arrays on the loop. A high error count for a particular component or storage array indicates that it might be experiencing problems and should be given immediate attention.
Error counts are calculated from the current
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Select the storage array from the
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To view error count data for a particular device, select the device from the Show devices on list. | ||||||||||||||||||||||
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Interpret the results to determine where problematic components or storage arrays are located. For more information, see Interpreting the Results. |
Error counts are calculated from a baseline (which describes the error count values for each type of storage array in the Fibre Channel loop), from the time when the baseline was established to the time at which the error count information is requested.
The baseline is automatically set by the RAID controller module; however, a new baseline might be set manually through the Read Link Status Diagnostics dialog by using the following steps:
Important: This option establishes new baseline error counts for all storage arrays currently
on the loop.
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Select Set Baseline. |
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Click Yes. |
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Click OK. |
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Click Run to retrieve the current error counts. |
Analysis of the Read Link Status results is based on the principle that the storage array immediately 'downstream' of the problematic component should see the largest number of Invalid Transmission Word (ITW) error counts. The process involves obtaining the ITW count for every component and storage array on the loop, analyzing the data in loop order, and then identifying any large jumps in the ITW counts.
If you are unable to determine which component is problematic, save your results, and forward them to Customer and Technical Support.
Use the following procedure to interpret the results:
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Open the Read Link Status Diagnostics dialog. |
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Look at the ITW column in the Read Link Status Diagnostics dialog, and identify any unusual increase in the ITW counts. Example An increase in the ITW column of 10 to 40 counts over a 24-hour period indicates that there is possibly a component or storage array in the loop that is experiencing problems. Typically, the ITW count should not change by more than a few counts over this period of time. Note: This is only an example and is not applicable to all situations. Important: Because the current error counting standard is vague about when the ITW error count is calculated, different vendor's storage arrays calculate at different rates. Analysis of the data must take this into account. Note: When analyzing Read Link Status (RLS) data for a storage array that contains both SATA physical disks and a RAID controller module in a single enclosure, you will see NA (not applicable) for each SATA physical disk in this enclosure. This is because the SATA physical disks are not communicating with the RAID controller module through the Fibre Channel (FC) protocol. However, if there are any SATA expansion expansion enclosures in the array, the EMMs in those enclosures are identified as Fibre Channel devices and report meaningful RLS data back to the RAID controller module. The SATA physical disks behind the EMMs report RLS data, but this data is coming from the Fibre-to-SATA translation circuitry in the EMM. |
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Click Close. If you are unable to determine which component is problematic, save your results, and forward them to Customer and Technical Support. |
For further troubleshooting assistance, save the read link status results and forward them to Customer and Technical Support for assistance.
Use the following procedure to save diagnostic results:
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Click Save As. |
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Select a directory, and type the file name of your choice in the File name field. You do not need to specify a file extension. |
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Click Save. A comma-delimited file containing the read link status results is saved. |