7 ms·

I was excited to until I read the limitations section. Can't be used as the startup disk and doesn't work with time machine. Hopefully this with change in the

I was excited to until I read the limitations section. Can't be used as the startup disk and doesn't work with time machine. Hopefully this with change in the next macOs release.

xd1936 10y ago
Sure, this is a developer preview. Final release in 2017 will surely make this FS the default.
- lewisl9029 10y ago
  That's what people were hoping for with ReFS from Microsoft, which released years ago, but that still hasn't happened yet.
  - whorleater 10y ago
    Apple is far more willing to switch to more newer technologies than Microsoft is.
    - mevile 10y ago
      One of the benefits of being vertically integrated.
    - drewda 10y ago
      ... and Microsoft is far more willing than Apple to put effort into backwards compatibility.
      - whorleater 10y ago
        I'm not saying Microsoft's approach is bad, just pointing out that there's a much higher chance of rapid adoption for this new filesystem.
      - criddell 10y ago
        In the past, nobody did a better job of backwards compatibility than Microsoft. Lately, Microsoft is showing that they aren't afraid to break things in the name of progress. If W10 is indeed the last version of Windows, maybe that's okay.
        Twisell 10y ago
        But wasn't that as the expense of clarity for new developers? I remember a horrible graduation exam where I had to code in VisualStudio. The Most harsh part was not coding or UI, it was determining which version of different window API had a remote chance to smoothly work together. (It involved DB drivers and data grids)
        criddell 10y ago
        Perhaps. But I suspect there's a lot more extending and maintaining existing software than writing new software. For the former, backwards compatibility makes a huge difference.
      - niccaluim 10y ago
        I don't know about that. Apple switched processor architectures twice, and both times software written for the old arch ran on the new one. And when they replaced their entire operating system, they not only made it so you could still program against the old API—just recompile and go—they also made it possible to run the old OS inside the new one so you could still run apps that hadn't yet been recompiled.
        duskwuff 10y ago
        And before that, when Apple made the 68k -> PPC transition in the mid-90s, they ran the whole system under a crazy, bizarre emulator that allowed for function-level interworking - 68k code could directly call PowerPC code, and vice versa. Early PowerPC systems were in fact running an OS that was mostly composed of 68k code; it wasn't until 1998 or 1999 (around the release of the iMac) that most of the Toolbox was ported to PowerPC.
    - catwell 10y ago
      Also, NTFS being a much better filesystem than HFS+, there was a lot less incentive to switch.
      - cordite 10y ago
        Too bad we still can't use NTFS flash drives on mac. Although ExFAT is at least somewhat promising.
  - Analemma_ 10y ago
    btrfs was available in the Linux kernel in 2009, but didn't see production release in the tinkerer-friendly distros until 2012 and in an enterprise distro until 2015. These things take time: filesystems need to be absolutely bulletproof, especially in the consumer space where (unlike Linux) most users will have no idea what to do if something goes wrong. I'd say Microsoft is still on schedule.
    - dmix 10y ago
      Speaking of which, is there any other good FS to use for desktop Linux (on an SSD on ArchLinux) or is Ext4 still the recommended standard?
      - qmr 10y ago
        XFS, ZFS, btrfs
      - mbakke 10y ago
        Depends on your needs. Stability, reliability: ext4/XFS CoW, snapshots, multi-drive FS: ZFS/btrfs SSD speed, longevity: F2FS
        snaky 10y ago
        I think it could be mentioned that most of the features regarding CoW and snapshots could be provided by LVM these days.
        lighttower 10y ago
        I've had F2FS on an Android tablet for many years. Resurrected it. However I'm running Debian on my laptop and I'm scared to try f2fs on / Because i get warnings about it being not fully supported "yet" i would love to have an SSD optimized FS on Linux. Since AAPL will open source the release version, is it conceivable that AFS could replace ext4 as the default Linux FS?
        snaky 10y ago
  - joelg236 10y ago
    Apple has (relatively, you can replace some harddrives) the most control on hardware, so at least from that perspective it's easier for them.
    - zrm 10y ago
      Control over hardware doesn't really buy you anything here. Just about any hardware can use any filesystem with, in the worst case, the requirement that you have a small boot partition using the legacy filesystem.
      - djcapelis 10y ago
        Interestingly with SSD storage devices, control of the hardware can help a lot more as it can become possible to categorize, fully explore and if needed, ensure a particular behavior of commands like TRIM. Other filesystems have the unenviable task of running on any random piece of storage you throw at it, including things where the firmware straight up lies, or the hardware delays non-volatility past the point the filesystem assumes (potentially producing data loss in a crash) or similar types of problems. Anyway. Overall, I think it's safe to say hardware control doesn't make most of filesystem development much simpler or easier. But there's a few interesting places it arguably does!
        zrm 10y ago
        That doesn't really change anything about the filesystem design. A storage device can fail to write data it claims to have because of damage as well as design defects. When that happens, a reliable filesystem will detect it and a less reliable filesystem will catch on fire. It also doesn't help to control 100% of the built-in storage if anybody can still plug in $GENERIC_USB_MASS_STORAGE_DEVICE and expect to use the same filesystem.
      - 0x0 10y ago
        Many filesystems exist that do not run on a "plain" read/write block device, because storage based on flash is more complicated than the old random-sector-access magnetic hard drives. See for example UBIFS and JFFS2 on Linux. Having full and direct low-level control of on-board SSDs could very well be advantageous for performance and longevity of the flash on modern macbooks. Things like combining TRIM with low-level wear leveling etc.
  - jug 10y ago
    OTOH Microsoft has a terrible track record of overpromising and underdelivering their next gen file system. I give Apple the benefit of doubt here. It is worded so that the limitations for the better part clearly sounds related to this being a preview release.
- trackofalljades 10y ago
  How can it be the "default" when you can't use it on a Fusion Drive or any system volume?
msbarnett 10y ago
This is a developer release. It's hardly likely that Apple is sinking dev resources into evolving a new OS filesystem without planning on the bootloader and backup functionality also being in place for the final release.
rbanffy 10y ago
Copy-on-write and snapshots are excellent building blocks for Time Machine, so much in fact that, when it was announced, I suspected it was because of ZFS (which, at the time, was being considered for OSX). It's very likely TM will be adapted to work on it (with about 20 lines of code)
- 0942v8653 10y ago
  I'm not sure about snapshots, TM is made to work by just copying the directory structure over, and each backup is a fully functioning hierarchy. But cloning is definitely a big deal.
  - cmsj 10y ago
    it doesn't "just" copy the directory structure over each time, it creates the structure for each backup, any files that are changed get copied in, ones that haven't changed are just hardlinked to the existing copies.
  - ysleepy 10y ago
    Well, consistency is important too in backups. So TM will probably make a snapshot and do the backup from there. Avoiding moved files from later dirs to already processed ones etc.
  - lobster_johnson 10y ago
    Time Machine uses hard links to create a duplicate directory structure without duplicating all the files themselves; only changed files need to be copied. As I recall, HFS+ was explicitly modified to support directory hard links, which is less common in the Unix world, explicitly to support this feature. TM also maintains a folder called /.MobileBackups to store temporary backups while your backup drive isn't connected. OS X also maintains /.fseventsd, a log of file system operations that TM can use to perform the next incremental, instead of having to compare each file for modifications.
  - rbanffy 10y ago
    A snapshot is a copy of the file (and its blocks) at a given point in time. Subsequent writes to it will happen to new blocks, leaving the ones connected to the snapshot undisturbed.
derefr 10y ago
"Can't be used as the startup disk" is not necessarily a strong limitation; with FileVault enabled, you start up from your Recovery partition anyway. Even if they lose FileVault, I would guess they'll keep the Recovery partition setup (since they've invested in it a bit as a pseudo-BIOS, for changing things like SIP.) So that image can stay HFS and hold your boot kernel, while "Macintosh HD" can just be APFS. Sort of like Linux with /boot on FAT32 and / in LVM.
- majewsky 10y ago
  /boot on FAT32 is mostly an artifact of UEFI these days. When I set up BIOS-based systems, I usually had /boot on ext2.
  - tempestn 10y ago
    Or even ext4. But I think the parent's point was that you'd keep your boot partition out of LVM.
- cmurf 10y ago
  Linux /boot tends to be on ext3 or ext4 on most distributions. Recently it's XFS on the server flavor of Fedora, CentOS, and RHEL. For openSUSE the default is Btrfs, /boot is just a directory. The bootloader/bootmanager is what determines what fs choices you have for /boot. GRUB2 reads anything, including ZFS, Btrfs, LUKS, even md/mdadm raid5/6 and even if it's degraded, and conventional LVM (not thinp stuff or the md raid support).
coldtea 10y ago
Those limitations are obviously because it's in development.
karmakaze 10y ago
The irony, a case-insensitive fs on case-sensitive "macOS"
- watersb 10y ago
  > Filenames are currently case-sensitive only.

I was excited to until I read the limitations section. Can't be used as the startup disk and doesn't work with time machine. Hopefully this with change in the next macOs release.

xd1936 10y ago

Sure, this is a developer preview. Final release in 2017 will surely make this FS the default.

lewisl9029 10y ago
That's what people were hoping for with ReFS from Microsoft, which released years ago, but that still hasn't happened yet.
- whorleater 10y ago
  Apple is far more willing to switch to more newer technologies than Microsoft is.
  - mevile 10y ago
    One of the benefits of being vertically integrated.
  - drewda 10y ago
    ... and Microsoft is far more willing than Apple to put effort into backwards compatibility.
    - whorleater 10y ago
      I'm not saying Microsoft's approach is bad, just pointing out that there's a much higher chance of rapid adoption for this new filesystem.
    - criddell 10y ago
      In the past, nobody did a better job of backwards compatibility than Microsoft. Lately, Microsoft is showing that they aren't afraid to break things in the name of progress. If W10 is indeed the last version of Windows, maybe that's okay.
      - Twisell 10y ago
        But wasn't that as the expense of clarity for new developers? I remember a horrible graduation exam where I had to code in VisualStudio. The Most harsh part was not coding or UI, it was determining which version of different window API had a remote chance to smoothly work together. (It involved DB drivers and data grids)
        criddell 10y ago
        Perhaps. But I suspect there's a lot more extending and maintaining existing software than writing new software. For the former, backwards compatibility makes a huge difference.
    - niccaluim 10y ago
      I don't know about that. Apple switched processor architectures twice, and both times software written for the old arch ran on the new one. And when they replaced their entire operating system, they not only made it so you could still program against the old API—just recompile and go—they also made it possible to run the old OS inside the new one so you could still run apps that hadn't yet been recompiled.
      - duskwuff 10y ago
        And before that, when Apple made the 68k -> PPC transition in the mid-90s, they ran the whole system under a crazy, bizarre emulator that allowed for function-level interworking - 68k code could directly call PowerPC code, and vice versa. Early PowerPC systems were in fact running an OS that was mostly composed of 68k code; it wasn't until 1998 or 1999 (around the release of the iMac) that most of the Toolbox was ported to PowerPC.
  - catwell 10y ago
    Also, NTFS being a much better filesystem than HFS+, there was a lot less incentive to switch.
    - cordite 10y ago
      Too bad we still can't use NTFS flash drives on mac. Although ExFAT is at least somewhat promising.
- Analemma_ 10y ago
  btrfs was available in the Linux kernel in 2009, but didn't see production release in the tinkerer-friendly distros until 2012 and in an enterprise distro until 2015. These things take time: filesystems need to be absolutely bulletproof, especially in the consumer space where (unlike Linux) most users will have no idea what to do if something goes wrong. I'd say Microsoft is still on schedule.
  - dmix 10y ago
    Speaking of which, is there any other good FS to use for desktop Linux (on an SSD on ArchLinux) or is Ext4 still the recommended standard?
    - qmr 10y ago
      XFS, ZFS, btrfs
    - mbakke 10y ago
      Depends on your needs. Stability, reliability: ext4/XFS CoW, snapshots, multi-drive FS: ZFS/btrfs SSD speed, longevity: F2FS
      - snaky 10y ago
        I think it could be mentioned that most of the features regarding CoW and snapshots could be provided by LVM these days.
      - lighttower 10y ago
        I've had F2FS on an Android tablet for many years. Resurrected it. However I'm running Debian on my laptop and I'm scared to try f2fs on / Because i get warnings about it being not fully supported "yet" i would love to have an SSD optimized FS on Linux. Since AAPL will open source the release version, is it conceivable that AFS could replace ext4 as the default Linux FS?
        snaky 10y ago
- joelg236 10y ago
  Apple has (relatively, you can replace some harddrives) the most control on hardware, so at least from that perspective it's easier for them.
  - zrm 10y ago
    Control over hardware doesn't really buy you anything here. Just about any hardware can use any filesystem with, in the worst case, the requirement that you have a small boot partition using the legacy filesystem.
    - djcapelis 10y ago
      Interestingly with SSD storage devices, control of the hardware can help a lot more as it can become possible to categorize, fully explore and if needed, ensure a particular behavior of commands like TRIM. Other filesystems have the unenviable task of running on any random piece of storage you throw at it, including things where the firmware straight up lies, or the hardware delays non-volatility past the point the filesystem assumes (potentially producing data loss in a crash) or similar types of problems. Anyway. Overall, I think it's safe to say hardware control doesn't make most of filesystem development much simpler or easier. But there's a few interesting places it arguably does!
      - zrm 10y ago
        That doesn't really change anything about the filesystem design. A storage device can fail to write data it claims to have because of damage as well as design defects. When that happens, a reliable filesystem will detect it and a less reliable filesystem will catch on fire. It also doesn't help to control 100% of the built-in storage if anybody can still plug in $GENERIC_USB_MASS_STORAGE_DEVICE and expect to use the same filesystem.
    - 0x0 10y ago
      Many filesystems exist that do not run on a "plain" read/write block device, because storage based on flash is more complicated than the old random-sector-access magnetic hard drives. See for example UBIFS and JFFS2 on Linux. Having full and direct low-level control of on-board SSDs could very well be advantageous for performance and longevity of the flash on modern macbooks. Things like combining TRIM with low-level wear leveling etc.
- jug 10y ago
  OTOH Microsoft has a terrible track record of overpromising and underdelivering their next gen file system. I give Apple the benefit of doubt here. It is worded so that the limitations for the better part clearly sounds related to this being a preview release.
trackofalljades 10y ago
How can it be the "default" when you can't use it on a Fusion Drive or any system volume?

msbarnett 10y ago

This is a developer release. It's hardly likely that Apple is sinking dev resources into evolving a new OS filesystem without planning on the bootloader and backup functionality also being in place for the final release.

rbanffy 10y ago

Copy-on-write and snapshots are excellent building blocks for Time Machine, so much in fact that, when it was announced, I suspected it was because of ZFS (which, at the time, was being considered for OSX). It's very likely TM will be adapted to work on it (with about 20 lines of code)

0942v8653 10y ago
I'm not sure about snapshots, TM is made to work by just copying the directory structure over, and each backup is a fully functioning hierarchy. But cloning is definitely a big deal.
- cmsj 10y ago
  it doesn't "just" copy the directory structure over each time, it creates the structure for each backup, any files that are changed get copied in, ones that haven't changed are just hardlinked to the existing copies.
- ysleepy 10y ago
  Well, consistency is important too in backups. So TM will probably make a snapshot and do the backup from there. Avoiding moved files from later dirs to already processed ones etc.
- lobster_johnson 10y ago
  Time Machine uses hard links to create a duplicate directory structure without duplicating all the files themselves; only changed files need to be copied. As I recall, HFS+ was explicitly modified to support directory hard links, which is less common in the Unix world, explicitly to support this feature. TM also maintains a folder called /.MobileBackups to store temporary backups while your backup drive isn't connected. OS X also maintains /.fseventsd, a log of file system operations that TM can use to perform the next incremental, instead of having to compare each file for modifications.
- rbanffy 10y ago
  A snapshot is a copy of the file (and its blocks) at a given point in time. Subsequent writes to it will happen to new blocks, leaving the ones connected to the snapshot undisturbed.

derefr 10y ago

"Can't be used as the startup disk" is not necessarily a strong limitation; with FileVault enabled, you start up from your Recovery partition anyway. Even if they lose FileVault, I would guess they'll keep the Recovery partition setup (since they've invested in it a bit as a pseudo-BIOS, for changing things like SIP.) So that image can stay HFS and hold your boot kernel, while "Macintosh HD" can just be APFS. Sort of like Linux with /boot on FAT32 and / in LVM.

majewsky 10y ago
/boot on FAT32 is mostly an artifact of UEFI these days. When I set up BIOS-based systems, I usually had /boot on ext2.
- tempestn 10y ago
  Or even ext4. But I think the parent's point was that you'd keep your boot partition out of LVM.
cmurf 10y ago
Linux /boot tends to be on ext3 or ext4 on most distributions. Recently it's XFS on the server flavor of Fedora, CentOS, and RHEL. For openSUSE the default is Btrfs, /boot is just a directory. The bootloader/bootmanager is what determines what fs choices you have for /boot. GRUB2 reads anything, including ZFS, Btrfs, LUKS, even md/mdadm raid5/6 and even if it's degraded, and conventional LVM (not thinp stuff or the md raid support).

coldtea 10y ago

Those limitations are obviously because it's in development.

karmakaze 10y ago

The irony, a case-insensitive fs on case-sensitive "macOS"

watersb 10y ago
> Filenames are currently case-sensitive only.