Company run by former ZFS Apple engineer

[Update: ZEVO web site is back up after prolonged outage] A former Apple engineer who worked on ZFS integration in Leopard and Snow Leopard has debuted a new software program to implement full ZFS support on the Mac. The alternative disk formatting, which offers a more efficient way to utilize disk space and actively prevents file corruption among other benefits, was touted by Sun Microsystems and considered by Apple as a possible replacement for HFS, but ultimately abandoned due to licensing issues.

Former Apple engineer Don Brady has since left the company and started one of his own called Ten's Complement, a reference to Mac OS X and its ability to support multiple file systems. In addition to HFS, the OS also reads and writes to FAT32 disks, UFS disks and has read-only support for NTFS (with supported write ability still present and exploited by third-party utilities).

ZFS was given limited read-only support in Leopard (OS X 10.5) and was scheduled for further development in Snow Leopard but was eventually dropped from the retail release, and the company ceased work on the project in 2009.

ZFS formatting creates a tree-based 128-bit checksum system for every bit of data stored on the drive, allowing the system to correct any file corruption on-the-fly, regardless of things such as power failures, system errors or driver bugs. It can also perform any corruption correction on mirrored or RAID drives, eliminating any need to run a filesystem check.

In addition, it uses a pooled storage model that doesn't require partitioning or provisioning (often used by SSD drives) and makes full use of the combined I/O speed of the computer and its attached devices, making it ideal for high-speed transfer technology like Thunderbolt. Another feature of ZFS is dynamic storage expansion, similar in theory to sparse disk images that can grow in size as additional data is added.

A ZFS disk would warn the user ahead of time if the disk was approaching capacity and could delay copy operations until additional storage was added on-the-spot. ZFS also boasts advanced "snapshot" capability for backups (similar to what Apple eventually created in Time Machine) and its own variation on RAID called RAIDZ which avoids "stripe corruption" common to RAID 5 during power outages.

Ten's Complement are offering the software, called ZEVO, in different editions depending on user need, with the basic Silver Edition" priced at $20. Internal storage drives (SAS, SATA HD or SSD) and external drives connected by USB 2 or 3, Firewire or Thunderbolt are supported. Files on ZFS drives are fully sharable using AirDrop, SMB (CIFS), FTP and AFP, though the latter is not yet fully supported on 10.7.2. ZFS drives do not yet support booting or disk encryption. The Silver edition is recommended for those who wish to try out ZFS on an external disk drive.

Also offered is a Gold Edition for $40 and adds Mac OS X Server compatibility, rotating snapshots, and RAID1 mirroring with self-healing. It will be made available sometime in early 2012, and is described by the company as "perfect" for a Mac Pro or an external drive with dual bays for RAID use. Users of any edition can upgrade to the next level as needed.

The Platinum Edition (pricing not yet announced) is expected to appear in the spring. The Platinum Edition adds both mirror and RAIDZ redundancy and is intended for those setting up and managing multiple-drive storage solutions. There will also be a Developer Edition that features conventional ZFS command-line tools, along with GUI options and other customization features.

The company is likely to work closely with the ongoing MacZFS open-source community that has spent the last few years building on the Apple and Sun work on ZFS to keep it updated.

by MacNN Staff