Data Domain: Disk Group Missing or Storage Unavailable

AFFECTED SYSTEMS:

• ALL Data Domain (DD) models 
• ALL Data Domain Operating System (DDOS) versions

SYMPTOMS: 

• STORAGE-00006: Disk group missing. One or more critical disks/LUNs are unavailable.
• FILESYS-00002: A problem is preventing the filesystem from running, typically due to unavailable storage.
• DDFS fails to start or goes offline.
• Backup operations fail due to inaccessible storage.
• Active Tier enclosures (such as, ES40, DS60) appear detached or offline.

CAUSE:

The filesystem is built on volumes composed of multiple disk groups (DGs), hosted on physical enclosures such as ES30 shelves or DS60 packs. DDFS requires uninterrupted access to these disk groups. Common causes include:

• Maintenance or upgrade activity
• Power loss or SAS connectivity issues.
• Faulty SAS HBA, cables, or Link Controller Cards (LCCs).
• Incorrect cabling topology

Restore connectivity to all attached storage enclosures and disk groups. Follow these steps to troubleshoot:

1. Identify Missing Components:
   Use DD-CLI commands to detect missing shelves or disks:

   # alerts show current  
   # disk show state  
   # storage show all  
   # enclosure show topology  
   

2. Compare with AutoSupport:
   Review recent AutoSupport logs to identify discrepancies in enclosure visibility.

3. Check Physical Connections:

   • Ensure that all enclosures are powered on and AC connections are secure.
   • Inspect and reseat SAS interlink cables.
   • Verify correct cabling topology.

4. Restore Filesystem Access:
   Once connectivity is restored, reenable the filesystem:

   # filesys enable  
   

5. Escalate if Needed:
   Contact your support provider if the issue persists or further diagnostics are required.

References:
- See appropriate Storage Shelf HW guide for cabling topology.

• Disk Shelf Guides