Good post by Hu Yoshida (thank you)
Surveys show that backup and restore remain at the top of the list of concerns for data centers. Each year as volumes increase, the struggle to meet SLAs and manage backup windows increases. Many enterprises with very large databases have come to rely on techniques such as simultaneously backing up data through multiple backup streams (multi-streaming) and backing up multiple sources to a single backup device (multiplexing). While these techniques can speed up backup dramatically, it makes it difficult to dedupe using traditional hashing techniques, which results in increased storage costs for backup.
Read on here