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Introducing Apple File System (APFS)
- Thread starter robE89
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HFS+ and its predecessors HFS and MFS were designed for a single processor, single thread, single user, and nominally single application environment. A such, many of the file system's internal data structures can only be accessed by a single thread at a time. This was not a problem as recently as the Core Solo Mac Mini. Today, many threads may have to wait until one thread is finished with its file system operations.
APFS splits the directory structure allowing multiple threads to make simultaneous file system changes.
For my first installation of 17A264c I wrote in some detail about issues involving encryption, but the link to my writing was removed.
The second installation, on a separate disk, failed in a more troubling way before I had an opportunity to test encryption.
So, could a program that is really great, but not efficiently multi-threaded -when compared to its cousin Logic X- could that unnamed really great audio editing program -also known for its random cpu-spikes and Quicktime Server process hangs- see an immediate boost in performance without rewritten code? (Currently written in C, C++, and Assembly.) -I won't mention any names, but its company's initials are A.V.I.D.
No. The operating system (OS) supports various types of file system.
HFS Plus and APFS are file systems. Quite different from each other.
Sierra and pre-release High Sierra support both HFS Plus and APFS.
Support for APFS is not release quality.
Don't know whom you were responding... To save anyone else the trouble of following a link, this is the first yellow highlight:
For the record: Apple is supposedly supporting searchfs (and FSCatalogSearch) on APFS. An involved engineer told me that they had added code for this mid-2016 because Spotlight relied on it and because they wanted to be fully compatible with HFS features ("including exchangedata and directory hard links"), although I believe to have learned that dir hard links are actually unsupported on APFS.
I wonder if the Apple intends APFS to be the default filesystem after the final version is released?
While the installer will currently ask if one wishes to use APFS what will happen if that option is removed?
Since its likely that not all software is going to be compatible with APFS at the release time I am not confident this is going to turn out well if Apple removes the option and if the installer converts to APFS without asking user...
While the installer will currently ask if one wishes to use APFS what will happen if that option is removed?
Since its likely that not all software is going to be compatible with APFS at the release time I am not confident this is going to turn out well if Apple removes the option and if the installer converts to APFS without asking user...
Actually, Apple has recently made a few changes (e.g. to the Unicode normalization issues) that should greatly reduce the issues with existing software.
So, I still expect Apple to encourage users to switch to APFS with the 10.13 update.
APFS will the the default file system for MacOS High Sierra. It won't be optional. That was announced at WWDC - it'll be the file system for all Apple products - iOS, tvOS, WatchOS, MacOS. It's already the file system for iOS - that was done very quietly by Apple, as part of the iOS 10.3 update - no option offered. In short, the biggest conversion has already been done, with great success.
Apple's execution of that iOS upgrade was "magical" - it took place without so much as a hiccup (see if you can find any "horror stories" here at MacRumors). They explained their approach afterwards. The conversion process provides for for automatic, 100% roll-back if the process fails. The original file system is preserved during the conversion process. They actually performed two dry runs during earlier iOS updates - the conversion was performed, then automatically rolled back afterwards. They knew it could be done, and then undone.
As to whether all software will be compatible... it is. While there are some new functions that can be (optionally) taken advantage of, all existing file system functions are supported. What APFS does when it receives a Copy command is different, but the result is transparent to the app and end user.
The primary task of the file system is to catalog and manage the location of every file block and unused storage location; to gather up all the pieces and deliver them in the proper order (Read) or determine where they can be stored (Write). When the APFS conversion takes place, nothing but the location of the file system catalog itself is moved/re-written. Everything else stays exactly where it was.
I appreciate the skepticism. Regardless of whether there's a file system conversion as part of an OS update/upgrade, I make sure I have a backup. However, if you think Apple hasn't thought this out very, very carefully, or doesn't fully appreciate the repercussions of errors or failure... to paraphrase Albert Einstein, Apple doesn't play dice with the file system.
Maybe you should come to my talk at Macoun.de early Oct to learn that that's not that simple
I noticed those changes in 10.12.6 but the question is are those changes enough? It seems only time will tell.
I am aware of the iOS filesystem change and while I don't use iOS devices I was surprised Apple did so without informing users and given them the option to decline the silent dry run. I would be furious if Apple does the same thing with macOS because while I certainly have backups I don't appreciate such attitude to customer data. In my opinion this was playing dice with customer data!
In theory conversion should have no problems but unlike iOS user and software have much more impact with filesystem in macOS and its likely many Macs have more complicated installations such as different partitions for older OS versions, separate data/ OS partitions etc. Personally while I do test the beta with 1 Mac I'm going to wait several updates before I consider using it for serious purposes because there is the risk that Apple didn't find all the bugs in testing...
As for the software compatibility given that practically every previous OS had changes that meant some software was not compatible I find it hard to believe that change in filesystem wouldn't cause any issues at all. While some software may work without updates I strongly suspect this will cause more problems than usually.
hoakley's article makes no mention of 10.12.6, and refers to Prepare for APFS in macOS High Sierra - Apple Support, which is currently dated 2017-09-05.
An earlier publication (2017-08-21) suggested that macOS 10.12.6 or later can read and write APFS. For me, that was not true with an encrypted APFS volume …
… maybe because I performed the encryption with a pre-release of APFS that's known to be incompatible with the planned release. Honestly, I can't recall the date of encryption. I do have various published notes but (sorry) it's not appropriate for me to link.
Right. Encryption is one case. There are probably others. One example I found is that if a folder contains hard links (which are, however, rarely used), then you cannot see the contents of that directory in 10.12.6).
I had some chats with Apple engineers and I got the impression that (a) it is known that 10.12.6 won't fully support APFS volumes created by 10.13, and (b) it's currently not planned to release a 10.12.7 update with an updated APFS driver that would solve all this.
And yes, this also suggests that if you create your APFS volumes in 10.12 you might keep compatibility both ways. Be warned, however, that I've seen cases where APFS on 10.13 immediately rewrite some structural parts of the volume, which in turn may lead to issues with 10.12.6 again. I'm still investigating the details of that. Also, I believe you cannot even create encrypted volumes in 10.12.6, or can you (haven't tried, just thought I read that somewhere).
[doublepost=1505636914][/doublepost]On another note, since people asked about backward compatibility:
1. If you manage to install High Sierra on an old Mac, then it may (if you boot from an SSD) or may not (if you boot from a HD, i.e. hard disk) convert all your volumes on the boot disk from HFS+ to APFS. As long as you keep using that Mac with High Sierra or later, you should expect no issues.
2. However, if you also keep using older Mac OS X versions, then those may not be able to access your new APFS volumes any more, as older OSX versions do not support APFS, and never will, at least not by Apple. The only exception is Sierra (10.12.6), which can read your APFS volumes created or converted under 10.13, as long as they're not encrypted. Older OSX version won't be able to access you APFS disks, though.
3. There is some hope, though: I am in the middle of writing a program that will at least give you read access to APFS volumes from any older Mac OS X version (10.6 and later, probably), as well as from Linux and Windows. I got it working on the command line level already, now I only need to write the user interface for it. Later, once Apple has published the specs, other 3rd parties may also come up with more solutions.
I am patiently awaiting feedback in this thread on how to approach High Sierra upgrades. Unless there's a general solution for older systems, then I could see myself wait quite some years before upgrading. I have at least one machine stuck on 10.11, and I want to know exactly what limitations I have over LAN, external drives and such.
Thumbs up! Are you planning on open sourcing it?
I've been doing some experimenting about how to prevent HS from converting HFS+ partitions to APFS. The odd thing is that I have one Mac where the conversion didn't happen, and it has several partitions, including Boot Camp. But when I try to replicate similar setups in VMware, it always converts them regardless. I'll keep looking though. If I find a way to prevent the conversion when installing HS, I'll share it.
Mostly likely not. I've spent already several weeks on figuring this all out, and I need to make a living from my computer work, as I have no other income. I can't afford giving all this away for free unless there's a way to get something back from open sourcing it. And that's not very likely. I plan to sell my app, maybe as shareware, similar to my Find Any File and iClip. You can always write your own, as at least the format analysis is open (I'm partaking in it): https://github.com/cugu/apfs.ksy
I do have 10.12.6 but I haven't tried. I read,
> … Apple has rendered the APFS commands in 10.12.6 effectively unusable for the creation of APFS storage or its containers, …
Afterthought
Given the absence of Sierra from Purchases in App Store, maybe Apple intends to very strongly steer users of Sierra into use of High Sierra.
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Time Machine won't back up onto an APFS disk at this point.
https://www.macobserver.com/tips/deep-dive/time-machine-and-apfs-need-know/
Anybody tried DriveDX 0.10 in High Sierra? They still recommend 0.8 driver for some reason.
https://binaryfruit.com/drivedx/usb-drive-support
https://binaryfruit.com/drivedx/kb#external-drive-support-macos-high-sierra
https://binaryfruit.com/drivedx/usb-drive-support
https://binaryfruit.com/drivedx/kb#external-drive-support-macos-high-sierra
I noticed a interesting take on the APFS given in Mac Sys Admin conference in Sweden:
https://blog.macsales.com/42819-video-presentation-taking-a-deep-dive-into-apples-apfs
According to the presentation APFS is currently about 50% slower on hard drive compared to HFS+, furthermore its not clear if Apple can optimize it given their focus is SSD and the underlying mechanic is completely different in hard drives.
This matches my own experiments with APFS in hard drive, too slow to be practical.
Another point raised by the presenter is the lack of documentation which means third party repair/ file recovery tools aren't 100% compatible with APFS. Good luck should one need to recover files from failed drive...
https://blog.macsales.com/42819-video-presentation-taking-a-deep-dive-into-apples-apfs
According to the presentation APFS is currently about 50% slower on hard drive compared to HFS+, furthermore its not clear if Apple can optimize it given their focus is SSD and the underlying mechanic is completely different in hard drives.
This matches my own experiments with APFS in hard drive, too slow to be practical.
Another point raised by the presenter is the lack of documentation which means third party repair/ file recovery tools aren't 100% compatible with APFS. Good luck should one need to recover files from failed drive...
Apple recently released partial APFS documentation: https://developer.apple.com/support/apple-file-system/Apple-File-System-Reference.pdf
It still lacks some details such as encryption but its a step in the right direction.
It still lacks some details such as encryption but its a step in the right direction.