Avamar: Instant Access Unmount fails with Invalid Client-List error during IA restore

Instant Access unmount failure

Attempting to unmount an Instant Access (IA) datastore from Avamar does not complete and returns an error.

• The Avamar UI shows the "Invalid client-list" error message during the unmount operation.
• The unmount process remains pending and never reaches a successful state.
• The NFS client associated with the IA export path is not listed when querying the Data Domain system.

Root Cause of IA Unmount Failure.

The IA unmount operation fails with the Invalid client‑list error because the NFS client (ESXi host) used for the IA restore is no longer present in the Data Domain configuration.

• The Data Domain NFS client list does not contain the ESXi host that initiated the IA restore.
• When the client is missing, Data Domain cannot resolve the export path, resulting in the Invalid client‑list error during unmount.
• If the /data partition on the Data Domain appliance is not mounted, the IA export directory becomes inaccessible, which can also trigger the same error.

Example of a missing NFS client on Data Domain:

# nfs show clients
No NFS clients found.

Example of a present NFS client (for comparison):

# nfs show clients
Path                                            Client          Options
------------------------------------------------ ---------------- ------------------------------
/data/col1/avamar-XXXXXXXXXX/VMDS/Avamar-MOD-XXXXXXXXXXXXX  X.X.X.X  (sec=sys,rw,no_root_squash,no_all_squash,secure,version=3)

Steps to Resolve "Invalid client‑list" Error During Instant Access Unmount.

Prerequisites

• Access to the Avamar UI.
• SSH access to the Data Domain system with administrative privileges.
• Network connectivity between the ESXi host and the Data Domain appliance.

Resolution Procedure

1. Identify the Instant Access (IA) job ID.
   Use the Avamar UI: Server > Data Domain NFS Datastores. Note the IA job ID displayed.
2. Confirm the ESXi host IP address.
   Run a Domain Name System (DNS) lookup for the ESXi host Fully Qualified Domain Name (FQDN) and verify that the returned IP matches the host.

   nslookup

3. Check existing NFS client mappings on Data Domain.

   nfs show clients

    If the ESXi host appears in the list, attempt an unmount from the Avamar UI first. If it does not appear, continue.
4. Verify the Avamar server Data Protection Node (DPN) ID.

   avmaint hfscreate

    The output shows the DPN ID (as in, XXXXXXXXXX). Record this value for later steps.
5. Ensure the /data partition is mounted on Data Domain.

   df -h

    If /data is not listed, mount it:

   mount localhost:/data /data

    Re‑run df -h to confirm the mount.
6. Locate the IA restore metadata (create.xml).
   Replace XXXXXXXXXX with the DPN ID obtained earlier.

   cd /data/col1/avamar-XXXXXXXXXX/VMDS/
   ls -l Avamar-MOD-XXXXXXXXXXXXX.vmds.info
   cat Avamar-MOD-XXXXXXXXXXXXX.vmds.info/create.xml

    If create.xml exists, proceed. If not, the IA export may already be cleared.
7. Map the ESXi host to the stale IA export path.
   Use the full export path and the ESXi host IP address.

   nfs add /data/col1/avamar-XXXXXXXXXX/VMDS/Avamar-MOD-XXXXXXXXXXXXX

    Note that the command is deprecated. The system suggests using:

   nfs export

    But it still creates the mapping.

    

8. Verify the new NFS client mapping.

   nfs show clients

    Confirm that the ESX host IP appears with the correct export path and options.
9. Unmount the Data Domain NFS datastore from the Avamar UI.
   Navigate to the datastore entry and select Unmount. A successful unmount displays a confirmation screen.
10. Confirm removal of the NFS client on Data Domain.
11. Run the client‑list command again:

nfs show clients

The ESXi host should no longer be listed.

Verification

• Attempt another IA unmount from Avamar. The operation should complete without the "Invalid client‑list" error.
• Check the Avamar UI for a clean status on the IA job.
• Confirm that no residual NFS client entries exist on Data Domain.