DS8000 Service Documentation Version 7.5

MAP5410 Fibre Channel bit error validation

Bit Error Rate Threshold incidents are caused by specific conditions at an interface or along a line which can cause bits to be received or interpreted incorrectly.

Before you begin

Note: Customer disruption may occur if microcode and power boundaries are not in the proper conditions for this service action. Verify that you start all service activities in Start here.

About this task

Bits that are received or interpreted incorrectly are counted. When a specific number is reached (threshold exceeded), the link is operating in a degraded mode. Bit errors are counted by each node attached on a link. You must determine which node(s) in a link have detected a threshold exceeded condition to identify the link or nodes causing the incident.
Note: Link errors (including "BER Exceeded"), when detected by the DS8000 host adapter, are usually caused by something external to the DS8000. The possible causes include the:
  • Optical cabling
  • Fibre Channel switch (if a switch is used)
  • System at the opposite end of the link (if directly attached, without a switch)

MAP5410 Section-1

Procedure

  1. Determine what type of error was reported by the customer or by the serviceable event.

    Was the error indicating a "Bit Error Threshold Exceeded " (BER) detected at the attached node (system or switch attached to the DS8000)?

  2. Display serviceable events that need repair. Are there any BER Exceeded (bit error rate exceeded) serviceable events (SRC=BE35264B) for the failing link?
    • Yes, continue with the next step.
    • No, additional link problem determination is needed. Ensure that all optical link cables are reconnected, then call next level of support.
    The problem appears to be external to the DS8000. Possible causes include:
    • Dirty or damaged Fibre Channel cables
    • Faulty port or adapter at the opposite end of the link
    • Faulty Fibre Channel connections
    • Incorrect Fibre Channel cable grade for the affected link speed
    This troubleshooting is outside the scope of DS8000 maintenance and is the responsibility of the organization supporting the customer's SAN or system/switch attached to the suspect/failing link on this DS8000.
  3. Run the bit error rate test on the desired Fibre Channel card port:
    1. At the management console, from the navigation area, click Storage Facility Management > storage facility.
    2. From the bottom Task area, click Service Utilities > Manage FRUs....
    3. Click Show I/O Enclosures.
    4. Select the I/O enclosure location and click Show Host Adapters.
    5. Select the host adapter and click Perform Bit Error Rate Test.
    6. Select the interface port to be tested and follow the instructions on the screen to run the test.
    Did the test run successfully?
    • Yes, close any outstanding BER Exceeded serviceable events for this link and resume any quiesced links. This call is complete.
    • No, return to the step in MAP5300 Fibre Channel link fault that sent you here.