Configuring the variable-length deduplication (VLD) algorithm for universal shares

The deduplication engine breaks the backup image into the segments and compares the segments to all of the segments that are stored in that deduplication node. Only the unique segments are sent to the NetBackup Deduplication Engine on the storage server. The Deduplication Engine writes the data to a Media Server Deduplication Pool.

See About variable-length deduplication on NetBackup clients.

NetBackup Deduplication Engine provides a couple of variable-length deduplication algorithm types. It brings better deduplication ratio if you use one variable-length deduplication algorithm for universal shares.

The variable-length deduplication algorithm is not enabled by default for universal shares, but the variable-length deduplication algorithm will be automatically enabled for MSSQL and Sybase applications. Use the vpfs_actions command-line utility to manage the algorithm configuration.

To configure the variable-length deduplication algorithm for universal shares

Navigate to the following location on the media server:
/usr/openv/pdde/vpfs/bin/
Run the following command to check the current configuration:
/usr/openv/pdde/vpfs/bin/vpfs_actions -a tune --imageId <share_id>
Sample output:
```
segment_type: "vld"
applications: [{"type": "vld", "sw_min": 16, "sw_max": 32}]
status: 0
```
Configure the variable-length deduplication version.
/usr/openv/pdde/vpfs/bin/vpfs_actions -a tune --imageId <share_id> --segment <VLD-version> --sw_min <sw_min> --sw_max <sw_max>
Note:
For the new environment where image backups do not exist in the storage, universal share automatically uses VLD v2 instead of VLD when you specify -segment VLD in the first-time configuration.

Option	Description
imageId	Unique identifier for the image.
segment	alignment Use fixed-length deduplication method. It's the default value. If set to alignment, sw_min and sw_max are not required. vld The version one of variable length deduplication algorithm. vldv2 The version 2 of variable length deduplication algorithm. It is recommended to use this version as default. vldv3 Another version of variable length deduplication algorithm.
sw_min	The minimum segment size (KB) of the segmentation range (16 - 127). Suggested values are 16, 32, and 64.
sw_max	The maximum segment size (KB) of the segmentation range (17 - 128), this value must be greater than sw_min. Suggested values are 32, 64, and 128.

Configuring the variable-length deduplication (VLD) algorithm for universal shares

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