Device Not Appearing in Multipath When Using NVMe-TCP on RHEL/Rocky/AlmaLinux

• Device visible in nvme list or lsscsi but not in multipath -ll
• Single path instead of multiple paths

• Device blacklisted
• Missing WWID
• Multipath not configured

Diagnosis:

# Check if device is blacklisted
multipath -v3 -d  # Dry run with verbose output

# Check multipath configuration
cat /etc/multipath.conf

# Check device attributes
udevadm info --query=all --name=/dev/<device>

Solutions:

1. Device blacklisted:
   • Check blacklist section in /etc/multipath.conf
   • Ensure device is not excluded
   • Add device to blacklist_exceptions if needed
2. Missing WWID:

   # Regenerate WWID
   /lib/udev/scsi_id -g -u -d /dev/<device>
      
   # Reload multipath
   multipath -r

3. Multipath not configured:
   • Verify multipath.conf exists and is valid
   • Restart multipathd: systemctl restart multipathd