ZFS

The ZFS filesystem seems to be too good to be true. A good presentation about ZFS major features is available.

Having instantaneous snapshots is something that I grew accustomed to with NetApp OnTap filesystem. I love the idea of having them in my servers. And if you believe the rumors flying around about Leopard, soon in a laptop near you.

Regarding the Mac, using ZFS as the basic filesytem for Mac OS X would be a superb move, and would give them for free all the technology to implement Time Machine. It would be only a pretty face on top of ZFS snapshots.

Next topics for R&D: OpenSolaris and OpenSolaris as a Xen client. The outlook looks good.

Update: as commented by Carlos Rodrigues, LVM also has snapshots. Yes, I knew that, but they are not as simple as NetApp or ZFS in terms of usage. I believe you have to specifically mount them, as can be seen in this example. I did find a couple of disturbing posts though. Also, I've read somewhere that snapshots are not resiliant to reboots, but haven't found a reference for that.