Why are there ZFS references in the latest iOS 5.1 beta?

Apple may have begun testing what appears to be ZFS (Zettabyte File System) support in the latest iOS 5.1 beta. If the information received by iMore is accurate. references to ZFS, including the mounting tools, are contained deep inside the system files. This raises a lot of questions about where Apple may be taking iOS storage in the future.

If you're not familiar with ZFS, here's Wikipedia's introduction:

ZFS is a combined file system and logical volume manager designed by Sun Microsystems. The features of ZFS include data integrity verification against data corruption modes, support for high storage capacities, integration of the concepts of filesystem and volume management, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Z and native NFSv4 ACLs. ZFS is implemented as open-source software, licensed under the Common Development and Distribution License (CDDL).

In other words, it's highly scalable and highly resilient, something you want in cloud environments. ZFS support was included in some earlier versions of Mac OS X, but was not included in the final, shipping version. Rumor has it Apple wasn't pleased when Sun spoke openly about Apple's adoption of their technology, leading Apple to pull the plug. Whether that's accurate or whether Apple simply determined it was going to go another way with OS X storage is unknown.

Even without official Apple support, we've seen OS X ZFS ports crop up since then. What sets this iOS implementation apart from some of the very original, official, OS X ports of ZFS is that it already contains the ZFS utilities (zpool, zdump, etc). By having the utilities already installed it means that the port is in a more complete stage of development and has full read + write access (unlike the original OS X ports).

So here's the question again, if this information is accurate, why is Apple looking to include ZFS in iOS? Could it be part of a greater plan to integrate better cloud services into future versions of the iPhone and iPad?

More: Wikipedia


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There are 15 comments. Add yours.

clint says:

Hopefully it's a sign that ZFS will still be coming built into OS X in the future.

AngriBuddhist says:

An Apple TV (set-top box) with an iOS compatible Time Capsule built right in!!!

denis says:

zdump has nothing to do with zfs!

Masatosama says:

Alas, no help for my old 3G, but at least 4.1 restores some of the pernromafce lost under 4.0. Now the big question is whether to get an iPhone 4 or a Droid. I'm well past my 2-year contract with AT T. It's like getting ouf of prison. (Or so I'm told.)

jackrv says:

ZFS has nothing to do with cloud services (on the client side). Also, ZFS does not benefit single-drive installations or devices not using RAID.

tangles says:

ah, ZFS most certainly "does" benefit single-drive installations.
checksum validation, meta correction, multiple file copies, compression, etc etc
The only thing zfs cannot do is perform real-time block repairs due to no redundant blocks residing on another drive.
This is a very interesting discovery...

smuckola says:

Hi there. I'm not sure why you're stating the ZFS has checksum validation and multiple block copies, but that it requires multiple drives in order to do repairs. The features you listed are precisely how it performs realtime repairs. ^_^ Even with just the default settings, generally speaking, any zpool is very redundant and is very hard to kill.

MrEdofCourse says:

This could be VERY big news.
iOS 5.1 may be the iOS launched with the iPad 3.
ZFS could solve a lot of issues involved with having an SD slot for expandable storage. Issues that Android based manufacturers solved by simply just releasing devices that sucked.

John Stalberg says:

I can't see much of a benefit from using ZFS on an iPhone? But a big drawback would be battery life cost and RAM sttarving the phone. Cloud stuff does its own fiesystem and doesn't need any client side ZFS. ZFS typically shines on servers with lots of storage, that's plugged in to the power supply all the time. It would be a waste of battery life on iOS-devices with hardly any benefits!

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smuckola says:

Hello from the http://MacZFS.org/ community. I'd sure like to get some substantiation to this. Even this screenshot is a rumor. It's just text. Do we know where it came from? Was it an internal-only build, or was it ever released to the public? Has it appeared in any other releases?

I maintain the MacZFS FAQ, so I made an entry for it just to address the rumor. Cool stuff!


And here's the FAQ about running it on a low end system with only one drive: