Troubleshooting Datastore Connectivity Issues in VMware ESXi

The Problem: Datastore Connectivity Lost

An ESXi host may lose connection to one or more datastores for several reasons:

1. Network Configuration Issues (for NFS/iSCSI): Incorrect IP settings or firewalls.
2. Storage Array Failures: Issues with the backend SAN or NAS hardware.
3. Pathing Problems: Multipath configuration errors or a single-path failure.
4. Corrupted Filesystem: Datastore metadata issues on the storage device.

How to Troubleshoot and Resolve

1. Verify the Storage Status in vSphere

• Navigate to Storage > Datastores in vSphere Client.
• Check if the affected datastore is listed and its status (e.g., Inactive or Not Connected).

2. Validate Physical Connections

• For iSCSI or NFS datastores:
  • Ensure the host’s VMkernel NICs are online and configured with the correct IP.
  • Test network connectivity to the storage target using ping or vmkping:

vmkping <storage-IP>

• For SAN-based datastores:
  • Inspect HBA (Host Bus Adapter) connections and verify the fiber cables or SFPs.

3. Rescan Storage Adapters

• Perform a manual rescan to detect any lost paths or devices:
  • Go to Host > Storage Adapters > Rescan All in the vSphere Client.
  • Alternatively, use SSH:

esxcli storage core adapter rescan –all

4. Check Multipath Configuration

Use the command:

esxcli storage nmp device list

Look for any inactive paths and troubleshoot based on the path state.

For active-active arrays, ensure the correct Path Selection Policy (PSP) is set (e.g., Round Robin).

5. Validate Storage Array Health

Log in to the storage array management interface to check for:

Controller failures.

Degraded or offline LUNs/volumes.

Restart the affected LUN if needed, ensuring no other hosts are dependent on it.

6. Recreate the Datastore Mount (NFS/iSCSI)

If the datastore remains inaccessible:

Unmount the datastore from the ESXi host.

Recreate the connection by adding the NFS or iSCSI target:

esxcli storage nfs add –host=<server-IP> –share=<nfs-path> –volume-name=<name>

 Repair Filesystem Corruption (VMFS)

• Use VMware’s built-in recovery tools to fix VMFS issues:

vmkfstools -R /vmfs/devices/disks/<datastore-ID>