Why can't I back up my FSx for ONTAP volume with AWS Backup?

Short description

If there's insufficient space on the file system, then backups commonly fail. Even if you have available space on the volume, the volume uses storage capacity from your file system for data that's stored in the volume. So, when you have available space on the volume, you still might not have available space on the file system SSD.

To create a backup of an FSx for ONTAP volume, Amazon FSx first verifies that the volume isn't full. You can't back up full volumes because FSx for ONTAP requires a small amount of free space to create a local snapshot. If a volume's utilization is above its threshold, then FSx for ONTAP considers a volume full. By default, the fullness threshold is 98%.

When FSx for ONTAP reports a volume's free space, it considers the available capacity that's smaller, either the volume's or the file system's SSD tier.

Resolution

Note: If you receive errors when you run AWS Command Line Interface (AWS CLI) commands, then see Troubleshoot AWS CLI errors. Also, make sure that you're using the most recent AWS CLI version.

To view failure messages for the backup, run the describe-backups AWS CLI command:

$ aws fsx describe-backups --backup-ids backup-xyzabc --region <region_id>

Note: In the preceding command, replace xyzabc with your backup's ID.

Because the backup that AWS Backup creates is stored in the .snapshot directory on the volume, the backup uses space on the volume.

Increase the space-full-threshold-percent to 100%

Because FSx for ONTAP volumes are thin provisioned, space issues might occur when you create snapshots. For example, if you create a 100 TB volume in a 1 TB file system, then use the NetApp ONTAP CLI to configure the space-full-threshold-percent.

The following NetApp ONTAP CLI command increases the full threshold of your volume so that FSx for ONTAP doesn't report your volume as full. The command also allows backups to proceed:

::> vol modify -vserver <svm_name> -volume <vol_name> -space-full-threshold-percent 100

For more information, see Managing FSx for Ontap volumes. Also, see Parameters on the NetApp website.

Increase the file system's SSD storage capacity

You can increase your SSD storage tier's capacity. For more information, see Updating file system SSD storage and IOPS.

Note: As a best practice, don't exceed 80% storage capacity utilization of your SSD storage tier. For more information, see When to increase SSD storage capacity.

Check the snapshot autodelete initiation setting on the volume

If your volume has snapshot autodelete turned on with the initiation set to snap_reserve, then your backup might fail. For more information about snapshot autodelete, see How to use Snapshot Autodelete on the NetApp website.

The snap_reserve parameter deletes snapshots when the space that's reserved for the snapshots reaches the value that's assigned in percent-snapshot-space. The default value is 5%. When you create a backup, Amazon FSx takes a snapshot of the volume, then compares the snapshot to the previous backup snapshot, if one exists.

Amazon FSx then copies only the changed data into the backup. When a previous snapshot has a larger size than the value that's assigned in percent-snapshot-space, the new backup automatically deletes at creation. So, Amazon FSx can't create backups of the volume.

To avoid this issue, increase the size of the volume so that the percent-snapshot-space parameter exceeds the size of the previous backup. The following example sets the percent-snapshot-space option to 20%:

::> volume modify -vserver <svm_name> -volume <vol_name> -percent-snapshot -space 20

For more information, see Manage the Snapshot copy reserve and Modify the Snapshot copy reserve on the NetApp website.

Related information

Working with backups

Working with snapshots

You have insufficient volume capacity