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Two bugs are described in this article: 1. An APFS volume's free space doesn't reflect a smaller amount of free space on the underlying disk 2. The diskimages

Two bugs are described in this article: 1. An APFS volume's free space doesn't reflect a smaller amount of free space on the underlying disk 2. The diskimages-helper application doesn't report errors when write requests fail to grow the disk image These are not even complex problems of the new format. It is just Apple forgot to have basic checks. It is like the root access with an empty password incident happened 2 months ago. Why these serious but basic problems happen? What is going on with Apple?

huslage 9y ago
(1) is incorrect. Sparsebundles are capable of over-provisioning the storage below them _by design_. They always have been. They are, I believe, APFS snapshots essentially now. This behavior is consistent with most other filesystems with similar constructs. (2) is the real issue here.
- dreamcompiler 9y ago
  > Sparsebundles are capable of over-provisioning the storage below them _by design_. According to TFA, HFS+ sparsebundles reflect the limitations of their underlying volume, while APFS sparsebundles do not. Seems clear to me that this is a bug.
- praseodym 9y ago
  Sparse bundle disk images [1] are a more efficient way to store disk images on an underlying file system. They are a completely separate concept from the file system in the disk image itself (besides HFS+ apparently doing some intelligent free space reporting) and are definitely not implemented as APFS snapshots. [1] https://en.wikipedia.org/wiki/Sparse_image#Sparse_bundle_disk_images https://en.wikipedia.org/wiki/Sparse_image#Sparse_bundle_dis...
alwillis 9y ago
This is by far the best explanation of what’s happening at Apple and why we’re noticing these bugs and problems: https://www.imore.com/understanding-apple-scale https://www.imore.com/understanding-apple-scale
- x0x0 9y ago
  Not really. If you built a new filesystem, competent software engineers will heavily test the corner cases. What happens when the fs runs out of space? What happens when the metadata store runs out of space? etc. The original article mentions bugs that are pretty obvious cases to test. What precisely happens when you have a sparsebundle that exceeds the storage capacity of the containing volume? A PM needs to define what should happen and an eng needs to test that it does. It's inexcusable that things like this aren't tested and is an organizational failure. This isn't some complex interaction of earbuds with watch and a cloud system. This is a very testable filesystem.
  - stormbeta 9y ago
    Agreed. Many of the issues with Apple's software quality lately are fundamentals, not issues of scale. Stuff like this, the root password bug, the many issues with reliability in High Sierra, etc. These things speak to organizational issues.
  - dingo_bat 9y ago
    Maybe they tested everything and didn't care. That's unlikely but possible.
    - x0x0 9y ago
      My guess is more that MacOS just gets the B or C team, and no-one involved was smart enough or diligent enough to think through the implications of sparsebundles that don't reserve space.
  - djsumdog 9y ago
    File systems are hard. They're incredibly difficult and incredibly important. It look a long time to get to ext4 and NTFS, and there's a reason HFS+ has stuck around for as long as it has, despite all of its shortcomings and limitations. Even in the Linux work, thinks like btrfs, even though some distros consider it sable, is still treated with scrutiny. Back in the early 2000s, many Linux distros refused to install on XFS or JFS. Apple's APFS rollout really does fell like it happened way too fast.
Macha 9y ago
Glass wall induced forgetfulness? https://thenextweb.com/apple/2018/02/17/apple-employees-keep-running-into-walls-at-its-new-spaceship-campus/ https://thenextweb.com/apple/2018/02/17/apple-employees-keep...
knolan 9y ago
> Apple forgot to have basic checks A common issue with Apple lately.

huslage 9y ago

(1) is incorrect. Sparsebundles are capable of over-provisioning the storage below them _by design_. They always have been. They are, I believe, APFS snapshots essentially now. This behavior is consistent with most other filesystems with similar constructs. (2) is the real issue here.

dreamcompiler 9y ago
> Sparsebundles are capable of over-provisioning the storage below them _by design_. According to TFA, HFS+ sparsebundles reflect the limitations of their underlying volume, while APFS sparsebundles do not. Seems clear to me that this is a bug.
praseodym 9y ago
Sparse bundle disk images [1] are a more efficient way to store disk images on an underlying file system. They are a completely separate concept from the file system in the disk image itself (besides HFS+ apparently doing some intelligent free space reporting) and are definitely not implemented as APFS snapshots. [1] https://en.wikipedia.org/wiki/Sparse_image#Sparse_bundle_disk_images https://en.wikipedia.org/wiki/Sparse_image#Sparse_bundle_dis...

alwillis 9y ago

This is by far the best explanation of what’s happening at Apple and why we’re noticing these bugs and problems: https://www.imore.com/understanding-apple-scale https://www.imore.com/understanding-apple-scale

x0x0 9y ago
Not really. If you built a new filesystem, competent software engineers will heavily test the corner cases. What happens when the fs runs out of space? What happens when the metadata store runs out of space? etc. The original article mentions bugs that are pretty obvious cases to test. What precisely happens when you have a sparsebundle that exceeds the storage capacity of the containing volume? A PM needs to define what should happen and an eng needs to test that it does. It's inexcusable that things like this aren't tested and is an organizational failure. This isn't some complex interaction of earbuds with watch and a cloud system. This is a very testable filesystem.
- stormbeta 9y ago
  Agreed. Many of the issues with Apple's software quality lately are fundamentals, not issues of scale. Stuff like this, the root password bug, the many issues with reliability in High Sierra, etc. These things speak to organizational issues.
- dingo_bat 9y ago
  Maybe they tested everything and didn't care. That's unlikely but possible.
  - x0x0 9y ago
    My guess is more that MacOS just gets the B or C team, and no-one involved was smart enough or diligent enough to think through the implications of sparsebundles that don't reserve space.
- djsumdog 9y ago
  File systems are hard. They're incredibly difficult and incredibly important. It look a long time to get to ext4 and NTFS, and there's a reason HFS+ has stuck around for as long as it has, despite all of its shortcomings and limitations. Even in the Linux work, thinks like btrfs, even though some distros consider it sable, is still treated with scrutiny. Back in the early 2000s, many Linux distros refused to install on XFS or JFS. Apple's APFS rollout really does fell like it happened way too fast.

Macha 9y ago

Glass wall induced forgetfulness? https://thenextweb.com/apple/2018/02/17/apple-employees-keep-running-into-walls-at-its-new-spaceship-campus/ https://thenextweb.com/apple/2018/02/17/apple-employees-keep...

knolan 9y ago

> Apple forgot to have basic checks A common issue with Apple lately.