Overview of TSM Integration
The following diagram shows a very simple, high-level overview of the LiteSpeed/TSM integration:
The server needs to have both the TSM client API software and LiteSpeed installed on the server.
TSM backups conducted through LiteSpeed are transferred to and then stored in and/or managed by the Tivoli Storage Manager. The TSM handles the LiteSpeed backup file from then on, managing expiration date, storage location, etc. The functions of the TSM are not discussed here, please refer to the product documentation for further details.
Because the application is cluster-aware, most users running SQL Server in a clustered environment can take advantage of LiteSpeed to send SQL Server database backups to TSM storage.
In a typical environment:
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Users who want to send LiteSpeed backups to TSM will have the machine from which LiteSpeed is run set up as a TSM client node.
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Because TSM works in a Client-Server implementation, this client node will point to the TSM Server. The client uses a configuration file called client option file to locate the TSM server. Generally, the TCP/IP address of the TSM Server and the port number that it is listening on are stamped in the client option file.
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The user conducts the backup/restores from LiteSpeed, using TSM-specific parameters.
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The TSM client processes the backup and restore requests from SQL server and translates them into TSM backup and restore requests.
(The above graphic is adapted from a similar image at www.redbooks.ibm.com).
Using LiteSpeed Compression
If you use LiteSpeed compression, the database pages will get compressed, and then the compressed data stream is sent to the TSM server. Database backup sizes within a range of 15-30% of the original database size are fairly common. This ensures the footprint of the backup on the network is minimal.
For optimal performance, you can use the Adaptive Compression feature. With Adaptive Compression, LiteSpeed will dynamically change the compression level based on available server resources.
For more information about the LiteSpeed compression options, please refer to the LiteSpeed User Guide.
Using Fast Compression
Fast Compression reduces the backup footprint another 70-85% over what you can already get with LiteSpeed compression. When configured, Fast Compression will intelligently back up only database changes rather than the entire database.
Using TSM Client-Side Data Deduplication
You can safely conduct backups through LiteSpeed, when TSM client-side data deduplication is enabled. Client based deduplication processing can reduce the amount of data being transferred over the network to the storage system, but there are often requirements for extra CPU and disk I/O processing on the client side. For more information, refer to the Implementing IBM Storage Data Deduplication Solutions guide available at www.redbooks.ibm.com.
Given that LiteSpeed can reduce backup size on average to 20% or less its original size, deduplication may be unnecessary as using LiteSpeed compression alone saves 5X or more disk space.