ZFS apparently coming to Leopard

by Jeremiah Foster

According to World of Mac the ZFS (Zettabyte File System) will be implemented in the upcoming Mac OS X release. This is pretty amazing news I think. According to Sun, who developed ZFS, the file system "is a fundamentally new approach to data management. We've blown away 20 years of obsolete assumptions, eliminated complexity at the source, and created a storage system that's actually a pleasure to use."

It has been suggested that the ZFS file system is being called Time Machine, which looks pretty good to me.

Yes, there is a touch of marketing speak there, from both Sun and Apple, but if it delivers on half of its promises, it will be a significant improvement on what we have today. Kudos Sun and Apple!


2006-12-20 04:54:43
ZFS is a file system that allows for addressing of stunning amounts of storage and is less dependent upon the nature of physical devices. Time Machine is backup software. Both are good, but one does not necessarily require the other.
2006-12-20 07:15:38
It seems to me that having something like ZFS in the OS makes a stronger case for using Apple in "enterprise" contexts...
2006-12-20 07:47:59
ZFS definitely sounds cool if it lives up to the hype. And it does mention that work is already underway to port it to BSD (from whence Mac OS X is derived).

But this is not the same as Time Machine. Time Machine isn't a file system... it's much higher level than that. It sits on top of an existing file system and primarily relies on Unix links to provide snapshots of the file system as it changes.

Thomas Fitzgerald
2006-12-20 10:33:30
I don't think ZFS is being called time machine. I think Time Machine may make use fo ZFS but that's a whole other debate. Either way it is great. Apple badly needs a new file system.
2006-12-20 10:37:42
Does this mean we'll get rid of the case insensitivity of the current Mac filesystem? That was a surprise when shifting over from Unixland.
2006-12-20 10:59:40
While ZFS is cool (I use it on Solaris at present) it *is* more or less very similar indeed to an older system called AdvFS that was prevalent on Tru64, albeit AdvFS didn't have a concept of storage pools for mirroring. They had 'domains' which had disks thrown into them and then storage simply mounted without format, very similar to ZFS. As you filled up disks you simply added another disk/partition/Veritas volume into the domain and kept using it. Neat.

Still ZFS is pretty hot. I imagine it would be best utilised in the MacOS server line-up as I'm really not sure what it will add to say my MacBook or iMac as HFS+ is perfectly adequate for that kind of use.

2006-12-20 11:31:49
There's an interesting interview with the makers of ZFS here:


But yeah, I don't think Time Machine is a front-end for ZFS features. Shame, as I think it might be smarter that way.

Zac Tolley
2006-12-20 11:50:49
ZFS is not time machine. Time machine is more likely to be based on a file system that has journal capabilities, and that is already there in the OS today.
2006-12-20 11:51:01

Take a look at /Applications/Utilities/Disk Utility. One of the volume format options is HFS+, case sensitive, and HFS+, case sensitive and journaled. (At least some (most?) applications really don't like this, so you use these on non-boot volumes.) And UFS is another option, it being case-sensitive, too.

Kevin Ballard
2006-12-25 21:46:04
Actually, Time Machine is completely unrelated to ZFS. Despite the fact that ZFS supports constant-time snapshots, and Time Machine is basically all about snapshotting your computer, Time Machine works on HFS+ disks and so it can't use any feature of ZFS at all.
Chris Hauser
2006-12-27 07:43:43
Info: In Leopard diskimages can be ZFS-formated.
Hint: Take a look at the implementation of FileVault.

Did you get an Idea about how Time Machine works?

2007-05-10 11:44:02
As I understand it, ZFS would replace BSD. Is that correct? What I can't seem to get my head around is how that would change application development, and what would be the security pros/cons of switching to ZFS?
2007-05-23 15:40:08

ZFS doesn't "replace BSD". The BSD subsystem is a set of tools and libraries used for programming or some Terminal hackery. ZFS is a file system, i.e. a way to store data on a disk. As long as Leopard knows how to read and write ZFS disks, any program that uses the provided libraries will continue to function normally, because - as a programmer - you normally don't really deal with low-level file system stuff. You simply tell the system to write or read a file and let the OS take care of the rest. For the most part, it doesn't matter whether you're dealing with HFS(+), UFS or ZFS.

So unless they're writing something like DiskDoctor (which needs low-level file system access), programmers shouldn't run into any problems using ZFS. They may be able to take advantage of some its features, but pretty much all apps that run on HFS+ should just as happily run on ZFS volumes.