Dell NetWorker 19.9 Administration Guide

Windows Optimized Deduplication

NetWorker supports backup of optimized data deduplication volumes and files and can restore optimized deduplication backups to a set of eligible restore targets. However, due to recovery performance issues observed with optimized backup for Windows deduplication volumes, it is recommended that you use non-optimized backup, which is enabled by default.

When the backup is set to non-optimized, NetWorker will not deduplicate the backup. Instead, the deduplicated files get rehydrated in memory before they are backed up. This type of backup requires you to enable VSS. If you disabled VSS (for example, by specifying VSS:*=off in the Save Operations attribute), the backup might back up the chunk stores unnecessarily. To back up the deduplicated volume, it is recommended to use block based backup (BBB) instead.

If you still require optimized backup, you can add VSS:NSR_DEDUP_NON_OPTIMIZED=no to the Save Operations attribute to restore settings to the traditional (non-BBB) optimized backup. However, it is not recommended that you use this setting because recovery performance issues might result in an unusable backup. Note also that even when optimized deduplication backup is enabled, NetWorker will not perform an optimized backup when the backup path is a subdirectory of the volume, or the non-optimized deduplication save option is specified in the Save operations field of the Client resource.

NetWorker supports the data deduplication feature on Windows Server 2012, Windows Server 2012 R2, Windows Storage Server 2012, and Windows Storage Server 2012 R2. NetWorker does not support the feature on Windows 8 client computers or computers that run the older versions of the Windows operating system. On computers that run the Windows Server operating system, NetWorker supports the feature on volumes that use the NTFS file system, which can be part of a fail over cluster, including CSV volumes.

To back up and restore Windows Server deduplication volumes or files, you must use a NetWorker 8.1 or later client. You can only restore deduplicated backups to computers that run on supported versions of Windows Server that have the data deduplication role enabled. The data deduplication role is a child role of File Services, which is a File and Storage Services role.