If we believe information reported by Jonathan Schwartz from Sun, Apple could use the ZFS as the default file system in Leopard.
If you want to know a bit more about ZFS, hereafter is the news we published last January about it:
Next version of Mac OS X, aka Leopard, will support Sun file system, known as ZFS for Zettabyte File System. What will be changed for Mac users?If the ZFS looks really promising, its default integration might be a new transition to be handled by Mac users.
First, ZFS is independent of HD storage space… quite almost has it supports up to 16 exaBytes HD, in other words 16 millions TB. Each file can use up to 16 exaBytes too. To compare with the current HFS+ file system in Tiger, we are "limited" to 16TB HD or a file while HFS+ support tops to 16 exaBytes too.
ZFS allows users to easily create ZFS storage pools (zpool), in other words disks are concatenated (something similar to LVM for Linux), or RAID-1 (mirroring) or RAIDS-Z volumes.
RAID-Z is an integrated redundancy scheme similar to RAID 5 (so an improved RAID 5, (see this page for more details about RAID-Z and RAID-Z2).
Another feature of ZFS that can be linked to the forthcoming Time Machine, is the support of snapshots. A snapshot is a copy of a set of files and/or directories as they were at a particular point in the past, so it makes "undo" or search of older version easier. Indeed, it uses the Copy-on-write functionality, making all modifications of a set of files written on a different location than the older version on the HD.
Another interesting feature is compression, a ZFS volume can automatically compress data (on-the-fly), adding extra storage space for users.
To conclude, managing zpools is relatively easy thanks to command lines as described in this article. One can expect that Leopard will allow users to manage zpools directly via the GUI of Disk Utility.
Of course ZFS is not perfect, there is currently no support for encrypting data, and journaling is not as easy as with HFS+. In addition, it is currently not possible to boot from ZFS volumes, even though they are working on this feature, when Apple releases Leopard, ZFS support might be initially limited to external volumes (non bootable) or might even limit this feature to OSX Server.
[update] Thanks to Dominik (from German website http://www.opensourcemac.de) for additional links and information below:
Concerning encryption when the zfs support is final:
http://www.opensolaris.org/os/project/zfs-crypto/
There are also some ppl working on the zfs_boot project.
Look at: http://blogs.sun.com/tabriz/
