I've wondered why no nas vendor had adopted data de-duplication. When you consider the number of files sent as e-mail attachments to 50 users and saved by five of them to their home directories, just file-level, single-instance data de-dupe would save most companies 20 percent or so of their file-server disk space.
So it's nice to see Network Appliance announce A-SIS (Advanced Single Instance Storage), which, for the first time, brings data de-duplication technology to primary storage. A-SIS goes further, implementing de-duplication on 4-KB blocks through NetApp's WAFL file system. Because WAFL stores data across the volume's space already, there should be a minimal performance hit reading de-duped files.
NetApp is giving away A-SIS to users of its NearStore products, which are frequently used as backup targets. FAS filer users can license A-SIS for $3,000--a bargain.