5.6 TSM Client-side deduplication Overview

• Less data travels over LAN because deduplication occurs during backup.

• Client nodes share the work with the server, identifying duplicate data.

• Requires processing to remove duplicate data that is no longer needed.

• Does not backup all data to the server.

• Became available in version6.2.0.

How to configure client-side deduplication ?

• Primary storage pool must be a sequential-access disk (FILE) storage pool that is enabled for data deduplication.

• Client-side data deduplication must be enabled on the server by using the DEDUPLICATION parameter on the REGISTER NODE or UPDATE NODE server command.

• TheDEDUPLICATION option on the client must be set to yes in the client options file.

• Filesthatareintendedfor deduplication cannot be excluded.

• Filewithencryption enabled cannot be deduplicated.

Client-side deduplication process

• The client creates extents. Extents are parts of files that are compared with other file extents to identify duplicates.

• The client and server work together to identify the extents that the client must send to the server for storage. Only those extents that are identified by the client that do not match extents that exist on the server are sent.

• The client sends the extents and hash values to a deduplication- enabled storage pool that the server manages. A hash value is a cryptographic irreversible data value that the hashing algorithm generates. The hash value enables comparing two values without the values being disclosed. Tivoli Storage Manager uses hash values to verify data integrity.

Benefits of client-side deduplication