ZFS to play larger role in future versions of Mac OS X

Sun Microsystems' relatively new ZFS filesystem will see rudimentary support under the soon-to-be released Mac OS X Leopard, but will eventually play a much larger role in future versions of the Apple operating system, AppleInsider has been told.

People familiar with the matter reveal that Apple on Wednesday provided developers with "ZFS on Mac OS X Preview 1.1" and associated documentation, in which the company asserted that it alone was responsible for porting the filesystem to Mac OS X.

The Cupertino-based firm also officially confirmed to developers receiving the pre-release software that Mac OS X 10.5 Leopard — due out later this month — will officially support ZFS, albeit restricted to a read-only implementation with which no ZFS pools or filesystems can be modified.

Developers receiving the latest ZFS preview, however, are granted access to full read and write capabilities under Leopard, including the ability to create and destruct ZFS pools and filesystems.

The developer release, those people familiar with the matter say, is a telltale sign that Apple plans further adoption of ZFS under Mac OS X as the operating system matures. It's further believed that ZFS is a candidate to eventually succeed HFS+ as the default file system for Mac OS X — an unfulfilled claim already made in regard to Leopard by Sun's chief executive Jonathan Schwartz back in June.

Unlike Apple's progression from HFS to HFS+, ZFS is not an incremental improvement to existing technology, but rather a fundamentally new approach to data management. It aims to provide simple administration, transactional semantics, end-to-end data integrity, and immense scalability.

According to Sun's description of ZFS, the filesystem offers a pooled storage model that completely eliminates the concept of volumes and the associated problems of partitions, provisioning, wasted bandwidth and stranded storage. Thousands of filesystems can draw from a common storage pool, each one consuming only as much space as it actually needs. Therefore, Sun says, the combined I/O bandwidth of all devices in the pool is available to all filesystems at all times.

In addition, ZFS provides a feature called "disk scrubbing," which is similar to ECC memory scrubbing; it reads all data to detect latent errors in the file system while they're still correctable.

"A scrub traverses the entire storage pool to read every copy of every block, validate it against its 256-bit checksum, and repair it if necessary," the description reads. "All this happens while the storage pool is live and in use."

A more comprehensive description of ZFS, along with several other features it offers, is available on Sun's OpenSolaris website.

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34 Comments

baranovich

said about 16 years ago

Does this mean that "complete" ZFS support might arrive in 10.5.5, or some such minor release???

Everything I've read about ZFS tells me that it is a great direction for Apple to in, I can't wait!

ozzyrocks

said about 16 years ago

Currently, we are able to freely move around files that are open in an application without causing any trouble in Mac OS X (mostly, at least), which is not possible with Windows or Linux. I believe I read that this was a feature of the HFS(+). Does this mean that once ZFS is adopted as the default FS, this will no longer be possible?

suhail

said about 16 years ago

Man? Apple is changing file-systems like there's no tomorrow!

booga

said about 16 years ago

Quote:

Originally Posted by ozzyrocks

This is possible in Linux and most UNIXes. In fact, most UNIX filesystems support the concept of the "inode", and if you have a reference to them you can keep using the file even after it's been "deleted". (In UNIX, the concept of "delete" is really just removing the last remaining hard link to the node, thus is termed "unlinking".) So I think ZFS will probably be better at this than HFS+.

The big thing that classic MacOS traditionally supported was the concept of a file id being the identity of the file on the file system, and the "path" being merely a convention. While somewhat similar to the inode in concept, Apple actually exposed it as the primary means to opening files in the old Toolbox. This allowed one to re-open the same file even after it moved from directory to directory without even knowing what directory it had moved to. While generally regarded as a great feature (and a feature that some of the database-oriented filesystems have also tried to use more recently), the UNIX-centric folks from NeXT won that battle fairly early in the MacOS X game and now the API is tied pretty tightly to the concept of locating a file via path.

jeffdm

said about 16 years ago

I thought that ZFS is a detriment for single drive systems, that it only really shines in a multi-drive system. Most computers that Apple sells can only hold a single drive. Pooling an internal drive with an external USB/FW drive doesn't sound like a good idea either.

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