ZFS To Become Default File System In Leopard

Macrumors noted, Sun’s CEO Jonathan Schwartz announcing that Apple would be making ZFS the default filesystem in Mac OS 10.5 Leopard. That’s a great news. So, welcome pooled storage and bye-bye volumes!

ZFS stands for Zettabyte File System and was developed by Sun, it offers many advanced features and can handle much more space than the current filesystems used by Windows, OS X or Linux.

ZFS presents a pooled storage model that completely eliminates the concept of volumes and the associated problems of partitions, provisioning, wasted bandwidth and stranded storage. Thousands of filesystems can draw from a common storage pool, each one consuming only as much space as it actually needs. The combined I/O bandwidth of all devices in the pool is available to all filesystems at all times.

All operations are copy-on-write transactions, so the on-disk state is always valid. There is no need to fsck(1M) a ZFS filesystem, ever. Every block is checksummed to prevent silent data corruption, and the data is self-healing in replicated (mirrored or RAID) configurations. If one copy is damaged, ZFS will detect it and use another copy to repair it.

ZFS introduces a new data replication model called RAID-Z. It is similar to RAID-5 but uses variable stripe width to eliminate the RAID-5 write hole (stripe corruption due to loss of power between data and parity updates). All RAID-Z writes are full-stripe writes. There’s no read-modify-write tax, no write hole, and — the best part — no need for NVRAM in hardware. ZFS loves cheap disks.