Avamar: NDMP backup completes with exceptions and "Could not resolve FILESYSTEM"

An Avamar NDMP backups fails with the following messages
 

2016-10-11 09:35:51 avndmp Error <0000>: [snapup-/ifs/XXXXXN/HOME/YYYYY] NDMP: Could not resolve FILESYSTEM /ifs/XXXXX/HOME/YYYYY - No error: 0
2016-10-11 09:38:08 avndmp Error <0000>: [snapup-/ifs/XXXXX/HOME/YYYYY] Backup for target /ifs/XXXXX/HOME/YYYYY had errors.


 

The file system is not accessible or does not exist

Troubleshooting:
Open the Avamar Administrator GUI > Backup and Restore window 
For the NDMP accelerator client, check if the filesystem noted in the log is visible.

Given errors noted above we would expect to not see the file system.

Check if the file system is available on the NAS.

If the NAS is Isilon it is possible to test for the existence of the file system outside of Avamar by browsing the web service with the following (example) curl command..

curl -vk -u "av-browse-admin" -X GET 'https://10.11.1.1:8080/namespace/ifs'
or

curl -vk -u "root" -X GET 'https://10.11.1.1:8080/namespace/ifs'
This example shows the directory /ifs.  Alternatively you could enter /ifs/XXXXXN/HOME/YYYYY
The command will display content under that directory.

• If the filesystem does not exist, it should be removed from the dataset
• If filesystem does exist, make sure it is spelled properly within the dataset
• If the file system does not exist, please remove the bad entry from the dataset and re-run the backup
• If the file system is seen using the curl command and matches the entry in the dataset please contact Avamar support for further assistance.

The Avamar Accelerator node avndmp process manages avtar processes which parse NDMP datastreams received from NAS devices

Where exceptions occur there are many possible causes.  
To investigate, first check the bottom of the avndmp log for the error count.
Review the file backwards to look for errors and warnings.