NetWorker: (NDMP) Error: "NDMP Service Error: SnapSure file system creation fails"

Summary: In a Network Data Management Protocol (NDMP) backup, the job stops due to a SnapSure file system creation error. Causes include low NAS space, wrong file system name, SnapSure timeout, file system corruption. ...

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Symptoms

Celerra/VNX NDMP backup failure. NDMP backup fails immediately with nsrndmp_save: NDMP Service Error: SnapSure file system creation fails

  • The SnapSure is the automatic NDMP checkpoint that the Celerra/VNX creates to back up a file system using NDMP.
  • SnapSure can be enabled in the NDMP Client 'Application information' attributes in NetWorker using the variable: "SNAPSURE=y".
  • SnapSure can also be enabled on the Celerra/VNX data mover for all NDMP backups using a setting in the NDMP server facility (default is disabled).
  • If SnapSure fails to get created for any reason, the NDMP backup fails immediately.

Cause

The most common causes of SnapSure creation failure are:

  1. There is not enough free disk space on the NAS to build the SnapSure checkpoint. The SnapSure takes disk space (called the SavVol) from the same disk pool as the file system that is being backed up. If there is not enough space to create the SnapSure, SnapSure creation may fail.

    From the Celerra/VNX Control Station, check which nas_pool the file system is built on:
nas_fs  i  [filesystem_name]

Check how much space is in the nas_pool:
nas_pool  size  all

If the SavVol is out of space, then the following may help resolve the issue:
  • Add more disk storage to the nas_pool in question.
  • Delete some existing checkpoints to free up space for SnapSure.
  • Increase the max SavVol size.
  • Direct the SnapSure to an alternate nas_pool or SavVol.
* Contact Dell Celerra/VNX Support for assistance with any of these resolution paths.
 
  1. The file system specified for backup is incorrect or does not exist. Check the save set names in the NDMP Client in NetWorker to make sure it exists and is spelled correctly (case sensitive). 
Verify the data mover file system name spelling by running the 'ndmpsup' utility from the NetWorker Server against the NDMP Client:

ndmpsup -c [ndmp_client] -o output.txt

Check the output.txt file for the file system names; they will be listed toward the end of the output file under.
*FS info for [file_system_name]*
 
  1. SnapSure creation fails if it does not get created within the specified timeout period. The default SnapSure timeout on the Celerra/VNX data mover is five minutes and can be extended up to 30 minutes. Typically, SnapSure gets created within a few seconds.
From the Celerra/VNX Control Station, check the SnapSure timeout value set on the data mover:
server_param server_2 -f NDMP -i snapTimeout
 
You can modify the snapTimeout value to the max (30 min), using the following command:
server_param server_2 -f NDMP -m snapTimeout -v 30
 
  1. SnapSure creation fails if enabled during NDMP backup of a checkpoint file system. This is because creating a checkpoint of another checkpoint is not possible and fails. This may occur more commonly when backing up an NDMP Client in NetWorker with SnapSure enabled and save set "All" - where all checkpoints may be included for backup along with regular file systems. In that case, multiple SnapSure failures may be observed, one for each checkpoint file system being backed up through the NDMP Client in NetWorker.

    You can verify whether checkpoint file systems are set to backup with save set "All." This is set in the NDMP server facility on the Celerra/VNX data mover and can be verified using the following command from the Celerra/VNX data mover:

server_param server_2 -f NDMP -i includeCkptFs
 

The setting can be changed to disable checkpoint FS backup with save set "All" using the command:
server_param server_2 -f NDMP -m includeCkptFs -v 0
 
  1. SnapSure failure can result from a code defect in DartOS. Check with Dell NAS Support for any related issues in the particular NAS version on the Celerra/VNX that may affect SnapSure creation.


From the Celerra/VNX Control Station, check the NAS model and version:

/nas/sbin/model
nas_version
 
  1. SnapSure failure may occur due to file system corruption or inode inconsistencies on the NAS disk backend. Running the nas_fsck utility against the file system in question is typically required to help resolve the issue in this case.

Resolution

  • Check and confirm the first two causes listed above as they are the most common reasons for SnapSure creation failure.
     
  • The best way to troubleshoot SnapSure creation failures is to collect the Celerra/VNX data mover server log immediately following the failed NDMP backup. The log should provide a descriptive enough reason for the SnapSure creation failure that aids in resolution. It may be necessary to set the NDMP logging on the data mover to debug mode for more detailed error collection.
To collect the data mover, log run the following command from the Celerra/VNX Control Station:
server_log server_2 -a -s > /nas/tmp/serverLog.out
 
You can view the log output file on the Control Station or FTP it to another host on the network.)
  • SnapSure can be disabled by removing the 'Application information' attribute "SNAPSURE=y" in the NDMP Client, or by setting it to "no" - "SNAPSURE=n."
  • SnapSure can be set as enabled on the Celerra/VNX data mover (default is disabled) using this command: 
server_param server_2 -f NDMP -m snapsure -v 1
  • By the same token, SnapSure can be disabled (if previously enabled) on the data mover using this command:
server_param server_2 -f NDMP -m snapsure -v 0
  • The setting in the NDMP Client 'Application information' attributes for "SNAPSURE=y/n" overrides the setting on the Celerra/VNX data mover.

Additional Information

SnapSure is a Celerra/VNX facility and is outside the control of NetWorker insofar as whether its creation succeeds or fails. NDMP backup fails immediately with SnapSure creation error. SnapSure is the automatic NDMP checkpoint for Celerra/VNX backups. Enable SnapSure in NetWorker or on the data mover. If SnapSure creation fails, NDMP backup stops.

Affected Products

NetWorker

Products

NetWorker Family
Article Properties
Article Number: 000068404
Article Type: Solution
Last Modified: 07 Jan 2026
Version:  4
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