Using VCT with accelerator for D-NAS
With NetBackup 10.2 onwards, you can enable accelerator along with VCT in the D-NAS policy for NAS backups. VCT along with accelerator technology is supported with Dell EMC PowerScale (Isilon), NetApp, Nutanix Files, and Qumulo NAS arrays.
With NetBackup 10.3, you can enable this feature for full schedule also, that enables the forever-incremental backup capability. After the initial full backup, no more full backups are required.
During full or incremental backups, NetBackup leverages the storage array vendor's technology to get the change-list (added, modified, and deleted files) between the two point-in-time snapshots. In the subsequent incremental or accelerator backups, NetBackup need not do a complete scan of the NAS volumes to determine the change-list.
After an initial full backup that protects all data from the filer, NetBackup accelerator backs up only the changed data from the filer to the media server.
Combining both these functions in a single backup policy, the backup window is reduced to full and incremental backups.
A regular full scan of the volume is performed for the full schedule with forced re-scan enabled in the schedule. NetBackup do not use the VCT information in this scenario.
Irrespective of the schedule, the change-list is obtained using VCT. This change-list is used as the source for backup.