Here's an excerpt from official TSM documentation for TSM Server 7.1 as a limitation for deduplication:
Encrypted files The Tivoli Storage Manager server and the backup-archive client cannot deduplicate encrypted files. If an encrypted file is encountered during data deduplication processing, the file is not deduplicated, and a message is logged. Can we get more information on this statement? How does TSM know that it has encountered an encrypted file? Is it based solely on include.encrypt options from the client? Will it look at the object metadata to see if it's encrypted? Will it try to post-process an encrypted file? In other words, if a file is encrypted say, using bitlocker or some third-party app, will TSM know not to process those objects for deduplication with the identify procedures? What's the overhead in calculating this scenario out? Has anyone tested this with TSM server 7.1? Thanks! Sergio