On 23 October, 2009 it was announced on MacOSForge that Apple had decided to discontinue any and all development on the porting of the ZFS file system. I know that I am not the only one to say this but I am not surprised. Supposedly there were legal reasons behind this action but in the end, who cares? They are the ones losing out to continue with an out dated and still limiting file system.
Now Apple has recently been hiring file system developers to develop a next generation file system to replace the traditional HFS+ but (as Robin Harris has previously stated) how long will it take before it becomes stable and accepted by the general public? Traditionally it takes 5+ years before a file system is considered somewhat stable and ready for production use. It wasn’t until recently that ZFS was starting to make its impact in the enterprise scene. Though my question is, to whom will this next generation file system cater to? I am to assume that it will be for the general end user utilizing Mac devices that “don’t require the weight of the ZFS features and functionality” ; or so it has been said regarding the topic of Apple abandoning the ZFS project. If that is the case and is the primary focus of the new file system, how will this impact their server market share? We already know that there is no such thing as a perfect file system that will perform ideally in every arena it is thrown into. Some will excel more than others and is entirely dependent on its implementation and workload.
In past posts, I have always stressed the importance of the file system and what is integrated within the file system. I routinely point out the numerous drawbacks and limitations of the NTFS driver. Sure, Microsoft compensates for the “lack of features” with applications, services and additional APIs to fill in all those gaps. A good example is VSS (shadow copy). This can impact performance as it is taking file system concepts out from kernel mode and into user land and consuming user mode resources. All these feature should and need to be incorporated into the file system driver. That way we can ensure that there is stability and consistency with all functions the file system performs. Even the general layout is not ideal for traditional computing over large storage media; as the fragmented large seeks between the MFT and the file data can put a lot of stress on the magnetic device. Going back to HFS+ and sort of on the same topic (although the concept is a bit different), the same could be said about Apple’s Time Machine and it running as an application on top of the driver.
One thing that I hold to heart when it comes to file systems is the ability and flexibility to tune it even without taking the mounted device(s) off-line. Most modern UNIX and Linux file systems offer a lot of tunable features (built into the driver!). For instance (through the ZFS character device node) I can dynamically alter file system variables (man 1 zfs). For this example I will focus on access times. Let us say I am using an SSD and decide that it would be more cell friendly and better performing to disable file access times on the root mount.
To view current settings and disable this feature you would type the following in the command-line terminal:
I just hope that Apple is prepared for the journey they are about to embark on. They obviously have file system development experience, and I have no doubts that they have the talent. Do they have the patience and time to invest?