Data Domain: Identifying a Defective or Inactive Link Controller Card (LCC)

Applies to:

• Data Domain systems with external storage shelves (ES30 or DS60)
• All DDOS software releases

Symptoms of a defective or inactive LCC can result in:

• Loss of multipath connectivity to enclosures
• Alerts indicating only one active path (instead of two)
• Disks reported as absent, failed, unknown, or degraded
• Irregular or unexpected link speeds on HOST or EXP'N ports
• Missing SAS paths to multiple enclosures
• Filesystem down due to missing disk groups

Common causes for LCC or SAS (MPATH) issues are:

• Hardware failure (LCC, SAS cable, HBA)
• Improper cabling or loose connections
• Power issues with the enclosure
• Firmware or software anomalies
• Site maintenance or upgrade activities

1. Check System Alerts:

• Run:

• # alerts show current

Review for disk or enclosure-related alerts that may indicate SAS connectivity issues.

2. Verify SAS Topology:

• Run:

• # enclosure show topology

Look for question marks (???) between enclosure paths, which indicate a possible fault in the controller or cabling.

Example Output:

Port      enc.ctrl.port             enc.ctrl.port           enc.ctrl.port
3a    >    5.A.H:5.A.E    ?  ?  ?    7.B.H:7.B.E      >      6.B.H:6.B.E

Error Message:
? - A possible problem was detected for this shelf controller or the cable connected to it.

If ??? is present:

• • Physically inspect and reseat SAS cables between shelves.
  • If cables are secure and alerts persist, escalate to Support.

3. Check LCC Status and Link Speeds:

• Run:

• # enclosure show controllers <Enclosure_Number>

Example Output (DS60):

• Encl 2
    Model                   DS60
    Capacity                60 Slots
    WWN                     N/A
    Serial #                JWXCD134400059
    Number of Controllers   2
  
    Controller A
      WWN          500604811015F07F
      Firmware     2.10.1
      Serial #     JWXCL134300134
      Status       OK
      HOST port    24.0 Gbps
      EXP'N port   48.0 Gbps
  
    Controller B
      WWN          500604811007517F
      Firmware     2.10.1
      Serial #     JWXCL134200021
      Status       OK
      HOST port    48.0 Gbps
      EXP'N port   0.0 Gbps

Example Output (ES30):

• Encl 3
    Model                   ES30
    Capacity                15 Slots
    WWN                     N/A
    Serial #                APM00134300555
    Number of Controllers   2
  
    Controller A
      WWN          50060480062C7CBF
      Firmware     1.55
      Serial #     CF23V132500362
      Status       OK
      HOST port    24.0 Gbps
      EXP'N port   24.0 Gbps
  
    Controller B
      WWN          50060480062D79BF
      Firmware     1.55
      Serial #     CF23V132500867
      Status       OK
      HOST port    24.0 Gbps
      EXP'N port   0.0 Gbps

Expected Link Speeds:

• • ES30: All links = 24.0 Gbps
  • DS60:
    • HBA to HOST port = 24.0 Gbps
    • Shelf-to-shelf EXP'N port = 48.0 Gbps
    • 0.0 Gbps indicates no physical link

Status: Should be OK
Firmware/Serial #: Blank fields may indicate a faulty LCC.

4. Physical Inspection

• Check for amber LEDs on the enclosure or LCC
• Ensure that AC power is connected and the shelf is powered on

5. Escalation

If the issue persists after basic troubleshooting:

• Generate a Support Bundle
• Raise a Service Request with your contracted Support Provider

REFERENCE (Additional Login authentication may be required to access these links)

- How to run SAS / Shelf Diagnostics
- Datadomain: Troubleshooting Adding a Shelf | Additional Storage/Enclosure
- Troubleshooting Autosupport Alert: Enclosure disk only has 1 active connection path and the required
- DataDomain: SAS Cable Configuration, Topology checks and Testing