Deduplication is one of the big hype topics in the storage world today. Deduplication is about finding blocks or files on a storage, that exist multiple times with the same content. For example one of this unfunny joke presentation mailed to a big mail alias, which got saved on 50% of the desktops. Deduplication find this blocks or files and leaves only one to the disk, replacing all others with a pointer to the remaining copy. The basic idea: Saving capacity by reducing redundancy. ZFS may have such an functionality in the future. Eric Kustarz writes in how dedupalicious is your pool? about some basics of such a functionality. The checksums integrated in ZFS may be of great use for Dedup, albeit you would use a cryptographically really strong hash algorithm. There is an BugID for this RFE at Hmm …. i hope this RFE will find it´s way to Opensolaris or Solaris soon. Think about a Thumper as a Backup2Disk device with automatically dedups all data coming to it´s disks. Or about an fileserver: Think about a combination of the in-kernel CIFS and the dedup functionality to save the storage needed for all this joke presentations. (found via Robert Milkowski)