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Comment by xaduha | Hacker News Reader

Is there any reason to use APFS on desktop?

There are a couple features missing from HFS+. Some of these are implemented in APFS: * Case sensitivity * Clones extents / ranges (reflinking) * Holes in the middle of files * ACLs * Collapsing file ranges * Per file compression and per file encryption

These are useful for apps like SQLite or other stores which implement a multi user, log structured store.

FYI - HFS is capability of case sensitivity and is an option during formatting. I believe it even used to be the default.

A quick note to any readers... I'd suggest avoiding a case-sensitive HFS+ boot volume with macOS. I used one for over a year, and it just brings trouble.

The biggest problems I encountered were (1) occasional bugs with Homebrew formulas, and (2) Adobe's applications cannot be installed on a case-sensitive file system.

HFS and HFS+ were never case-sensitive by default on Mac OS. Case-sensitive HFS+ was made available as an option in Mac OS 10.0, but was always glitchy (especially for boot volumes), because many applications depended on case insensitivity.

I think possibly the point of confusion is that very early versions of MacOS X (the original MacOS X server, and some of the MacOS X DPs, anyway) used UFS by default, not HFS+. UFS is case sensitive.

I have a case sensitive HFS+ and everything works fine.

That was a problem with older versions of Adobe suite, but since lots of people on Macs used Adobe Apps...

Isn't the problem still present? A few months back I tried installing the latest version of Photoshop and Illustrator, and it didn't let me.

> was always glitchy (especially for boot volumes), because many applications depended on case insensitivity.

So CS HFS+ is not glitchy, and CS APFS will not magically fix applications with CI dependency.

What about snapshots? Does APFS offer efficient user-created snapshots? I run Ubuntu with btrfs, and for me this is a killer feature.

> Does APFS offer efficient user-created snapshots?

Yes: https://arstechnica.com/apple/2017/02/testing-out-snapshots-...

I'm hoping it will make Time Machine a lot better.

Isn't there a flag to make hfs case sensitive? Programs react poorly because it's rare, but it's available.

FWIW, HFS+ fully supported NFSv4 ACLs since... no idea, but they were already there in 2008.

I believe one reason APFS is touted is because the HFS+ data structures have one big global lock, whereas APFS allows for multithreading which ought to improve performance on multi-core machines.

I heard there will be copy-on-write for files. For web devs this would save a lot of space and time when copying files from yarn cache to node_modules.

I wonder what it means for appending data to a large log file. Does the entire log file need to get copied on every write (or just a block of the file?)

My hope is that it will improve Time Machine performance / reliability.

COW should do wonders for performance, but COW with no data checksums would make me more nervous about reliability (only one copy of files to corrupt)

I agree to a point, one factor that can help mitigate this however is using a quality SSD where it's onboard memory has ECC, I suspect Apple sees the near future of end user computing as gaining ECC for all memory by standard which is something I've wanting for years but games have been played by CPU manufacturers to prevent the use of high end desktop CPUs in server environments by I believe purposely kneecapping them from using ECC memory (citation probably needed here).

  > but games have been played by CPU manufacturers

Plural? Intel and who else?

I was trying to be nice ;) hehe

I haven't done any serious analysis of Time Machine (or of APFS for that matter), but I think in general Time Machine also only keeps one copy of files. So APFS isn't worse than the existing situation. Arbitrarily keeping multiple copies blows up the disk requirements. You can intentionally keep old copies around in APFS via snapshots, which is what APFS will probably do when implementing Time Machine.

What Apple added for the existing Time Machine on HFS+ was an extension of the Unix concept of hard links to files (where there is only one copy). They added hard links to directories. Generic Unix avoids doing that for a number of reasons.

Isn't is already true that there is one copy to corrupt? The whole idea of using hard-linked trees (a la rsnapshot [1]) presumes that when a file doesn't change, there is only one copy.

[1] http://rsnapshot.org/

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