PPDM: Troubleshooting NAS Backup Failures - ABNA0016, ABNA0023, Mount Errors, and Configuration Issues

Error Messages

"Unable to mount the share path [SHARE_PATH]"

"Unable to mount CIFS share — permission denied or authentication failure"

"NAS proxy network connectivity failure after initial mount resolution"

"getxattr(system.cifs_ntsd) failed with errno=11 — resource temporarily unavailable"

"Error on initializing file" — illegal SMB characters or multiple ss files in chunking

Backups running for hours on small shares (e.g., 126GB taking 7+ hours)

ABNA0016 - Unable to Mount Share Path.

• Incorrect share name - the share name in PPDM does not match the exact name on the NAS array.
• Incorrect NAS Server network interface - backup traffic is routed through the wrong interface, causing time‑outs or connection refusals.
• Share name contains special characters ($, spaces) - trailing $ or spaces are unsupported by the mount process.
• NFS protocol not enabled on PowerScale - CIFS backups require NFS to be active for internal PPDM operations.
• Issue PDM02-458 - a known defect that causes consistent mount failures regardless of configuration.

ABNA0023 - Unable to Mount CIFS Share (Permissions)

• Insufficient permissions on Isilon/PowerScale - the backup user lacks Full Control or the BackupAdmin role.
• CIFS hostname vs. IP resolution - using an IP address instead of the FQDN leads to Kerberos/NTLM mismatches.

NAS Credential and Timeout Issues

• getxattr errno=11 - resource temporarily unavailable, typically on large shares with many files.

File Name and Change list Issues

• Illegal SMB characters in file names - trailing spaces, characters exceeding 255 bytes, or other unsupported symbols cause initialization errors.

NAS Proxy Sizing and Performance

• Undersized NAS proxy for large file counts - shares with millions of files take excessive time to back up

NAS Proxy Connectivity Issues

• NAS proxy network connectivity failure (ABN0013) - after an initial successful mount, subsequent backups fail due to proxy‑to‑array network problems

ABNA0016 - Resolution Steps

1. Go to Protection > Protection Policies > [Policy] > Assets. Verify that the share name exactly matches the NAS export path, including case sensitivity. Correct the share name and retry.
2. Go to Infrastructure > Storage > [NAS Array] > NAS Servers. Ensure the correct network interface (backup/data network) is selected, not the management network. Rerun discovery after correction.
3. If the share name contains special characters ($, spaces), either create a new share alias without them or include the exact name with the character. Test with a manual backup after configuration.
4. On the PowerScale/Isilon, verify that the NFS protocol is enabled on the access zone using PowerScale OneFS > Protocols > NFS > Global Settings.
5. If the issue persists and matches the known defect, upgrade PPDM to a version containing the fix for issue PDM02-458. Contact Dell Support for the current fix availability.

ABNA0023 - Resolution Steps

1. On the Isilon/PowerScale, ensure that the backup user account has Full Control permissions on the SMB share and is assigned for the BackupAdmin role (or equivalent) and is a member of the Backup Operators group. Rerun discovery and retry the backup.
2. Configure the NAS server using its FQDN instead of an IP address. Remove the existing entry and readd using the FQDN. Verify DNS resolution from the PPDM appliance (such as, nslookup [NAS_FQDN]).

Credential and Timeout - Resolution

1. Add or readd the NAS user credentials directly to the asset (not only to the policy).
2. Increase the asset timeout to 6 hours and set the retry count to 3.
3. Isolate the failing asset and run a forced level=full backup while no other NAS backups are running.
4. After the forced full completes, resume the normal synthetic full schedule.
5. Consider excluding constantly open files that cause conflicts.

Illegal SMB Characters - Resolution

1. Identify files with illegal SMB characters using the NAS array's file‑scanning tools.
2. Rename or remove files containing illegal characters, trailing spaces, or names longer than 255 characters.

NAS Proxy Sizing - Resolution

1. Check the number of files on the share. If the share has more than 10 million files, deploy a Medium or Large NAS proxy.
2. Refer to the PPDM Administration Guide for NAS proxy sizing recommendations based on file count.
3. Assign the larger proxy to the protection policy and retry the backup.

NAS Proxy Connectivity - Resolution

1. Verify network connectivity between the NAS proxy and the NAS array (ping, telnet on ports 111, 2049, 2052).
2. If connectivity is confirmed, redeploy the NAS protection engine: Infrastructure > Protection Engines > [NAS Engine] > Redeploy.
3. After redeployment, rerun discovery and retry the backup.

Prevention — Best Practices