Avamar: NDMP Backup Fails With Signal 11 Segmentation Fault Due to Inode List Memory Limit

Observed Backup Failures and Errors.

During NDMP backups of NetApp volumes, the following symptoms are commonly reported:

• Backup jobs terminate with a segmentation fault (Signal 11).
• Avamar logs show plugin processes exiting with Signal 11.
• Backup history retrieval fails for the affected volume.
• Workorder execution reports a non‑zero exit status caused by Signal 11.

2022-12-20 01:00:11 avndmp Info : [snapup-/XXX/YYY] Plugin process 1444 exited with signal 11 (0x8b); wait 1444, code 0: success
2022-12-20 01:00:11 avndmp Info : [snapup-/XXX/YYY] Plugin exited with 'Signal 11 exit - Segmentation fault'
2022-12-20 01:00:11 avndmp Error : [snapup-/XXX/YYY] pipe wait has non-zero exit status when trying to get backup history list for '_2XXX_2FYYY'
2022-12-20 01:00:11 avndmp Warning : [snapup-/XXX/YYY] Problem retrieving backup history for volume: /XXX/YYY
2022-12-20 15:41:30 avndmp Info : [ctl_spawn] Process 1552 (/usr/local/avamar/bin/avtar) finished (Signal 11 exit - Segmentation fault)
2022-12-20 15:41:30 avndmp Warning : [ctl_spawn] CTL workorder "NDMP_Sched-NDMP_1_Policy-1671498000006#01" non-zero exit status 'Signal 11 exit - Segmentation fault'

Caution: Repeated segmentation faults indicate that the backup process cannot handle the current inode list size.

Resolve Signal 11 (Segmentation fault) in Avamar NDMP backups.

Option 1 - Reduce the backup target list.

Split the dataset into smaller groups so the inode list fits within the memory Avamar reserves.

• Identify the volume or share that generates the error.
• Create one or more new datasets that contain a subset of the original files/directories.
• Assign the same NDMP policy to each new dataset.
• Run a test backup for each new dataset and verify that the Signal 11 error no longer appears.

Option 2 - Enable disk‑based inode buffering

Configure Avamar to write the inode table to disk instead of RAM by adding the --stream-disk-buffer flag.

Method A - Using Avamar Administrator (UI)

• Open Avamar Administrator and navigate to the affected dataset.
• Click More Options. The Backup Command-Line Options dialog appears.
• Select More.
• In the Enter Attribute field, type avtar .
• In the Enter Attribute Value field, type stream-disk-buffer=true .
• Click Add to save the attribute.
• Save the dataset and run a backup to confirm the issue is resolved.

Method B - Editing avtar.cmd (CLI)

Append the flag directly to the command file used by the NDMP client.

# Change to the NAS client variable directory
$ cd /usr/local/avamar/var/[CLIENT_NAME]

# Open avtar.cmd with a text editor (vi, nano, etc.)
$ vi avtar.cmd

# Add the following line (or append to existing options)
--stream-disk-buffer

Save the file and restart the Avamar client service if required.

Verification

• Run a backup of the affected volume.
• Open the avndmp log (e.g., /var/log/avamar/avndmp.log ) and confirm that there are no entries containing Signal 11 exit - Segmentation fault or "Problem retrieving backup history.”
• Check that the backup history list is populated correctly in the Avamar console.