Installation and User's Guide

vvvvClient-side data deduplication must be enabled on the server. To enableclient-side data deduplication, use the DEDUPLICATION parameter on theREGISTER NODE or UPDATE NODE server command. Set the value of theparameter to CLIENTORSERVER.Files on the client must not be excluded from client-side data deduplication. Bydefault, all files are included. You can optionally exclude specific files from datadeduplication.Files on the client must not be encrypted. Encrypted files and files fromencrypted file systems cannot be deduplicated.Files must be more than 2 KB. Files that are 2 KB or less are not deduplicated.The server can limit the maximum transaction size for data deduplication bysetting the CLIENTDEDUPTXNLIMIT option on the server. See the Administrator'sGuide for details.The following operations take precedence over client-side data deduplication:v LAN-free data movementv Subfile backup operationsv Simultaneous-write operationsv Data encryptionImportant: Do not schedule or enable any of those operations during client-sidedata deduplication. If any of those operations occur during client-side datadeduplication, client-side data deduplication is turned off, and a message is writtento the error log.The setting on the server ultimately determines whether client-side datadeduplication is enabled. See Table 10.Table 10. Data deduplication settings: Client and serverValue of the clientDEDUPLICATIONoptionSetting on the serverData deduplicationlocationYes On either the server or the client ClientYes On the server only ServerNo On either the server or the client ServerNo On the server only ServerEncrypted filesThe Tivoli Storage Manager server and the backup-archive client cannotdeduplicate encrypted files. If an encrypted file is encountered during datadeduplication processing, the file is not deduplicated, and a message is logged.Tip: You do not have to process encrypted files separately from files that areeligible for client-side data deduplication. Both types of files can be processed inthe same operation. However, they are sent to the server in different transactions.As a security precaution, you can take one or more of the following steps:v Enable storage-device encryption together with client-side data deduplication.v Use client-side data deduplication only for nodes that are secure.v If you are uncertain about network security, enable Secure Sockets Layer (SSL).Chapter 2. Configure the Tivoli Storage Manager client 41