(1) (Zettabyte File System) A distributed file system from Sun that was added to OpenSolaris in 2005 and Solaris 10 in 2006. With support for 128 bits, compared to 64 for NTFS and other contemporary file systems, storage capacity is unlimited for all practical purposes, which is the reason for the "zettabyte" name. ZFS supports up to 18 quintillion virtual storage pools (zpools), each of which can hold 18 quintillion drives or drive partitions. Because of this titanic capacity, its storage is considered unlimited.
(2) (zFS) (zSeries File System) A distributed file system from IBM for its zSeries mainframes. In zFS, storage management is separated from file management. zFS "front ends" reside in all the machines that use the system, and all files are created and written to "object store devices" (OSDs), which perform the physical disk writes. zFS has a unique cooperative caching mechanism. It will use the data found in the cache of one of the other computers in its cluster before it goes to the disk. Disk accesses are always the slowest.