Knowledge Base

Calidate that each troubleshooting step below is true for your environment. Each step provides instructions or a link to a document, in order to eliminate possible causes and take corrective action as necessary. The steps are ordered in the most appropriate sequence to isolate the issue and identify the proper resolution. Do not skip a step.

These steps assist you in identifying a LUN connectivity issue:

1. Verify that the LUN is presented to the ESX host. You may need to contact your array vendor for assistance.
   
   
   1. Verify that the LUN is in the same storage group as all the ESX hosts (if applicable to the array).
   2. Verify that the LUN is configured correctly for use with the ESX host.
      
      Note: Consult the appropriate SAN configuration guide for your array (listed in the Additional Information section).
      
      
   3. Verify that the LUN is not set to read-only on the array.
      
      
2. Verify that the ESX host can see the LUN(s). For more information, see Obtaining LUN pathing information for ESX hosts (1003973).
   
   Note: If LUNs are not visible on the ESX host, see:
   
   
   • For fibre-channel LUNs: Troubleshooting fibre channel storage connectivity (1003680)
   • For iSCSI LUNs: Troubleshooting iSCSI array connectivity issues (1003681)
   
   
3. Verify that a rescan restores visibility to the LUN(s). For more information, see Performing a rescan of the storage (1003988) and Interpreting SCSI sense codes (289902).
   
   
4. Check the storage for latency. For more information, see Using esxtop to identify storage performance issues (1008205).
   
   
5. Verify that SCSI reservation conflicts are not in excess. For more information, see:
   
   
   • Analyzing SCSI Reservation conflicts on VMware Infrastructure 3.x and vSphere 4.x (1005009)
   • Resolving SCSI reservation conflicts (1002293)
   • SCSI Reservation Issue with Fibre Channel HBAs (4365932)
   • Insight Manager may cause excessive SCSI reservation conflicts (1004771)
   • Unable to create a VMFS3 partition on a metaLUN or LUSE LUN (1000286)
     
     
6. For issues related to the VMFS datastore, see:
   
   
   • Troubleshooting VMFS-3 datastore issues (1003964)
   • Unable to create a VMFS3 partition on a metaLUN or LUSE LUN (1000286)

Note: If your problem still exists after trying the steps in this article:

• Gather the VMware Support Script Data. For more information, see Collecting Diagnostic Information in a VMware Virtual Infrastructure Environment (1003689).
• File a support request with VMware Support and note this KB Article ID (1003955) in the problem description. For more information, see How to Submit a Support Request.