# Faster Incremental Backups for Amazon FSxN File Servers and Data Protection Volumes Using NetApp SnapDiff

Applies to: CIFS and NFS only

You can use SnapDiff for faster incremental backups for regular backups of NAS file servers (network shares). SnapDiff is a NetApp feature that identifies which files changed between snapshots, so that backups do not have to traverse the entire file system to determine which files changed.

On NetApp storage arrays, all IntelliSnap backups of network shares use SnapDiff. You can also use SnapDiff for regular backups of network shares.

SnapDiff is especially effective when you have a large number of files that do not change a lot between snapshots.

Note

For NetApp storage array, the junctions between volumes are not supported.

## Support for NetApp Data Protection Volumes

You can use SnapDiff to perform faster incremental backups of the NetApp Data Protection (DP) volumes from the NetApp secondary array. This feature helps to protect secondary volumes (DP volumes) where access to the primary array is restricted.

To use this feature, do the following:

- Configure the sDPVolumePrefix additional setting on the NAS client. For information on how to configure an additional setting, see Adding a Setting for Servers and Server Groups.

- Mount the DP volumes and create the CIFS or NFS shares on DP volumes.

- Grant ‘Full Control’ access of the CIFS share on the destination array for an impersonated user.

- A latest snapshot of the secondary volume with prefix value as configured in the additional setting must be available on the DP volume before performing backup of the share using SnapDiff. Complete the snapmirror update on the destination array so that latest snapshot is available.

- Ensure that the access node has access to the destination array where the DP volume is present.

## How SnapDiff Works

The first full backup job creates a baseline snapshot. A snapshot is created, data is scanned by traversing the file system, a snapshot is created, and then data is backed up from the snapshot.

Subsequent backups are incremental. SnapDiff identifies the data that changed by comparing the previous and current snapshots, without traversing the file system. Data is then backed up from the snapshot.

At the end of each job, snapshots created by the previous job are deleted from the array, and only one set of snapshots is retained on the array.

The scan operation that traverses the file system is used only in these cases:

- The snapshot from the previous job is not available

- The snapshot creation fails in the current job

- The SnapDiff operation fails

## Related Topics

- Verify that your environment meets the system requirements for SnapDiff.

- To compare the performance of backups with SnapDiff to backups without SnapDiff, see Metrics for NAS File Server Backups with SnapDiff.

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