ZFS On Mac: Now All-But-Official

by Robin Harris on Sunday, 17 December, 2006

Update: It is official. See here. Then come back and read the rest of this post. Thanks to alert reader Oskar for the tip.

French website Mac4Ever reports – thanks to Babelfish translation:

. . . the few innovations of Leopard, one read these last months, several rumours on the integration of a new filing system, the ZFS, which presents a revolution in the field of the storage of data. This rumour seems to be confirmed, since one sees finally apparaitre in the utility of discs of Leopard, an option to create images and partitions in this format.

They include this section of a screenshot:

Which seems pretty convincing. Or at least someone had fun with Photoshop. For the record, I believe.

I forget, so why is this cool?
See ZFS On Leopard: How Cool Is That? for more details, but the main coolness is:

  • No more disk utilities. The entire data store is self-validating.
  • No RAID controllers needed: ZFS gives you fast RAID for free. Just add drives.
  • No more volumes and, therefore, no more volume management. ZFS eliminates the whole volume concept. Add a disk to your system and it joins your storage pool. More capacity. Not more management.
  • Easy, fast backup through snapshots which means that Time Machine could give you a view of your data every hour on the hour, all day long.

But That’s Not All!
For in-depth treatment of ZFS see here and here. Includes links to more technical info and benchmarks.

FWIW, StorageMojo called it first . . .
Competitive analysis is not for the faint of heart, and I confess I wavered on whether or not Apple was really doing ZFS, until the iTV announcement three months ago. Then it all became clear – to me – while the silence from the rest of the Mac community was deafening (see Means, Motive & Opportunity: Apple Kills the Media Center PC). I even tried to bet the inimitable John Siracusa of Ars Technica a drink – only to find he doesn’t bet or drink!

The StorageMojo take
Why is this even slightly important? For the same reason I said four months ago:

StorageMojo.com has devoted time to this issue because today’s computer business is largely driven by consumer computing, not enterprise computing. Putting a really modern integrated file and storage management system on a consumer OS would raise the bar for everyone else.

No doubt Apple will first recommend ZFS for Mac OS X Server, just as they did with HFS+. Yet it won’t be long before it becomes the default file system, and not a moment too soon.

Update: I updated this post with some additional explanatory material, for those few people who haven’t been following ZFS and Leopard as avidly as I have.
YAU: Looks like Leopard’s Disk Utility also supports iSCSI natively. Another plus.

Comments welcome, of course.

{ 5 comments… read them below or add one }

hmurchison December 18, 2006 at 9:48 am

I was wondering when you’d write a piece on the new ZFS info. It looks like a nice start and perhaps by 10.6 ZFS will be the preferred fs for the entire OS. I would not have a problem with that. We don’t need RAID controllers when in 2006 the avg Mac will have 4 cores.

ZFS is important as we begin to move towards Terabyte drives. Keeping that massive amount of data incorrupted is important.

Wes Felter December 18, 2006 at 12:57 pm

Now will Apple replace Xserve RAID with Xserve JBOD?

Robin Harris December 18, 2006 at 3:28 pm

I suspect it will become the default sooner than 10.6. Home users actually put a lot less stress on a file system than servers do. So if they’ve got the uitlities built for homies to manage it, I’d guess 10.5. 4.. The Solaris version has been out for a year now, so it is getting solid.

I don’t know what they are going to do with the Xserve RAID.. FC is great for distance and speed, but I think a lot of folks would be happy with SAS and saving another several hundred bucks. Yet if you run RAID 0, you have access to all the drives, and you need the controller to MUX the FC-to-ATA traffic anyway. Of course, they could run FC-AL, but I would have to believe that would be a support nightmare for them, unless you limited the number odrives to a real small number.

Given that Leopard has native iSCSI support, another interesting possibility emerges for the low-end. How about, and you heard it here first! – an iServe RAID. ISCSI RAID box on Gig E. Same packaging, different controllers. $100 Gig E switch instead of the $1400 FC switch. Slower, but a lot of folks won’t care.


Todd February 1, 2007 at 7:50 pm

As of January 2007 Solaris zfs backups are rudementary and not why I used zfs. In most places day to day restores are file recovery operations. Recovering an entire filesystem should only be necessary following a massive failure. All zfs restores depend on restoring a full filesystem. There are ways to make a zfs backup system work, but they are not beautiful like raidz2, three way mirrors and instant filesystems.

Basically you snapshot the filesystem and send the snapshot data to a tape or a file or to another zfs command. There don’t seem to be any error messages. What I mean is that you don’t really know if your backup is any good. How’s that from the people who checksum the data on every write and protect it with double RAID and hot spares.

Let’s assume the backup worked. If you want to restore a file you need to pull the entire filesystem off the tape and convert it into a file system:
zfs receive tape or a file or a pipe”
The result of sending a zfs snapshot to a tape or file is a single large file. There is no way to extract a particular file or get a list of the contents. You can send it through a pipe to “zfs receive somenewzfs”. It creates an entire copy of the filesystem, which is great when you have the space – night after night.

Dave Mount May 16, 2007 at 6:41 pm

Robin, I wanted to comment off the zdnet posting as it tends to get zealot crazy, that I appreciate your article. Thanks!
Also, as someone who earns a living from selling Apple systems and OS X-native apps to professionals (medical and dental), it is important to me to be able to provide them with information that will be an incentive to have them invest in Apple technology. With ZFS implemented in OS X, the braininess of Sun engineers will be of practical benefit to my clients whose entrustment of *their* clients’ medical information, is of utmost importance. Just another buttress in the system that will convince users that the Mac platform design is all over what Jobs’ “user experience” is all about!

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