Data Domain: SAS or MPATH Alerts

Summary: All Dell Data Domain (DD) systems use SAS connectivity to provide path redundancy (multipath) for attached enclosures and disks. If communication is interrupted along any part of the SAS path, the system generates alerts to notify administrators of potential issues. Prompt attention to these alerts is essential to maintain system health and data availability. ...

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Symptoms

Applies to:

  • All Data Domain (DD) models with External Storage attached
  • All Data Domain Operating System (DDOS) versions

Each DD system maintains two SAS paths to every enclosure and its disks. A typical data path includes:

  • PCIe SAS HBA → SAS HBA Port → SAS Cable → Enclosure Controller (LCC) → Disk

Failure at any point in this path can trigger alerts or event IDs. While alerts may indicate the fault, further investigation is often required.

Common SAS and MPATH Events:

EVT-MPATH-00003: Missing disk connection from system port Nx
EVT-MPATH-00005: Enclosure Disk only has active connection(s); required number is 2
EVT-MPATH-00006: Path redundancy to an enclosure is lost
EVT-SAS-03801: Enclosure cables on port have been connected incorrectly
EVT-SAS-03802: The HBA port is disabled
EVT-SAS-03803: The SAS HBA in slot has failed

Cause

Common causes of SAS or Multipath events are:

  • Incorrect cabling or topology
  • Site maintenance or upgrades (such as adding or upgrading storage, power maintenance, accidental cable disconnection)
  • Loose or improperly seated SAS cables
  • Faulty hardware (HBA, SAS cable, LCC, or disk)
  • Transient firmware or software faults

Resolution

Always restore full SAS multipath connectivity. Do not leave missing or degraded paths unresolved.

Recommended Actions:

  1. Run Diagnostic Commands (to identify where the fault lies):

alerts show current
disk port show summary
disk port show stats
enclosure show topology
enclosure show controllers <n>
disk multipath status
disk rescan <n.n> (where n.n is the Enclosure.Slot reference)
  1. Compare with previous Autosupport:
  • Use a preevent Autosupport to identify missing or degraded connections.
  1. Physical Inspection:
  • Disable the file system (filesys disable) before reseating or moving any SAS cables.
  • Check SAS and power cables for secure connections.
  • Look for missing LEDs or fault indicators on controllers.
  1. Reference Documentation:
  1. Escalation:
  • If further assistance is needed, generate a Support Bundle and raise a Service Request with your contracted Support Provider.

Affected Products

Data Domain, PowerProtect Data Protection Appliance, Data Domain Deduplication Storage Systems, Integrated Data Protection Appliance Family, PowerProtect Data Protection Hardware
Article Properties
Article Number: 000204344
Article Type: Solution
Last Modified: 17 Nov 2025
Version:  6
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