PowerScale OneFS 9.8.0.0 Web Administration Guide

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Snapshot-based incremental backups

You can implement snapshot-based incremental backups to increase the speed at which these backups are performed.

During a snapshot-based incremental backup, OneFS checks the snapshot that is taken for the previous NDMP backup operation and compares it to a new snapshot. OneFS then backs up all files that were modified since the last snapshot was made.

Dell Technologies recommends snapshot-based incremental backup when the change rate is under 2%.

You can perform incremental backups without activating a SnapshotIQ license on the cluster. Although SnapshotIQ offers several useful features, it does not enhance snapshot capabilities in NDMP backup and recovery.

Set the BACKUP_MODE environment variable to SNAPSHOT to enable snapshot-based incremental backups and ensure that the DMA is sending the correct BASE_DATE and BACKUP_OPTIONS. If you enable snapshot-based incremental backups, OneFS retains each snapshot that is taken for NDMP backups until a new backup of the same or lower level is performed. However, if you do not enable snapshot-based incremental backups, OneFS automatically deletes each snapshot that is generated after the corresponding backup is completed or canceled. Also, BACKUP_OPTIONS changes how many snapshots are kept and if periodic manual deletion is needed.

NOTE:A snapshot-based incremental backup shares the dumpdates entries in the dumpdates database along with the other level-based backups. Therefore, ensure that you do not run snapshot-based backups and regular level-based backups in the same backup paths. For example, ensure not to run a level 0 backup and snapshot-based incremental backup in the same backup path or the opposite way.

After setting the BACKUP_MODE environment variable, snapshot-based incremental backup works with certain data management applications (DMAs) as listed in the next table.

Table 1. DMA support for snapshot-based incremental backups This table displays DMA support for snapshot-based incremental backups.
DMA	DMA-integrated
Generic	Enabled only through an environment variable.
Backbone	Enabled only through an environment variable.
CommVault	Yes, and can be enabled through the NDMP environment variable.
Dell NetWorker	Yes, and can be enabled through the NDMP environment variable.
Veritas	Enabled only through an environment variable.
Tivoli	Enabled only through a cluster-based environment variable.
Veritas Backup Exec	Enabled only through a cluster-based environment variable.