back to article A computer file system shouldn't lose data, right? Tell that to Apple

Apple's recently revised file system, APFS, may lose data under specific circumstances, a maker of macOS backup software is warning. In a blog post on Thursday, Mike Bombich, creator of Carbon Copy Cloner, says that APFS sparse disk images fail to accurately track available free space, thereby allowing storage operations to …

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Beware of Claims

When a product says that it won't stain, it stains. When a pen claims to be leak proof get a pocket protector. When a company brags that quality is job one...

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Tell me it ain't so

Apple's products increasingly riddled with functional and security problems, polish no longer that much above the polish you can get from a regular budget hardware maker pushing stuff out on a shoestring and scrabbling for a razor-thin profit margin.

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What the hell?!

Is this the 1980s again? This was a common thing back in the last century. How the hell is happening again?

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Mushroom

Re: What the hell?!

I blame Agile development, it might work for some things, but nothing mission critical.

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Re: I blame Agile development

Personally I think development methodology has less impact than team quality, experience and management attitude - if you have a team where they are all in 20s and management concentrating on target features and release dates, chances are you are going to have lots of issues in code. Get a good team with sufficient experience and management who understand that just because someone is half the hourly wage doesn't make them twice the value and shouting doesn't make problems go away - then you'll generally have less issues

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Anonymous Coward

"...fail to accurately track available free space..."

Design, Coding, Peer Review, Requirements Tracability, Testing, QA, and Documentation.

A partial list of the failure points for this to make in into the wild.

Oh, and Management too. Because it's their job to make sure that the others do theirs.

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New file system

Writing a reliable modern filesystem is hard. That Apple did so in just a few years and have rolled it out to millions of devices without any major disasters so far is very well done!

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Re: New file system

Agreed. I've seen bugs like this in sparse file handling in commercial Unix file systems several times over the last 25 years. You have to be imaginative about test cases to predict use cases although ENOSPC seems kinda obvious to me. Thinking Different shouldn't equal magical thinking.

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Re: New file system

But nobody ever completely fills a drive, they always throw away the machine and give us more money every two years!

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Re: New file system

Designing a modern reliable car is difficult. The fact that Ford/Citroen/... did so within a few years and rolled it out to millions without the wheels falling off very often is very well done.

?Hmm

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Re: New file system

I think the trick lies in not re-inventing the wheel. ..

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Re: New file system

No major disasters? Maybe because the majority of people haven't filled their media up yet?

Even a filesystem that makes a complete mess of fragmenting files will appear "reliable" as long as there's sufficient space to hold a file without resorting to fragmentation...

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Apple SVP of software engineering Craig Federighi insisted, "There's nothing we care about more,"

What, not even money?

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Boffin

Interesting.

In the Blog post 'Mike B' says

"This week we reported to Apple a serious flaw in macOS that can lead to data loss when using an APFS-formatted disk image. Until Apple issues a macOS update that resolves this problem, we're dropping support for APFS-formatted disk images."

Then he goes on to say that it only affects 'Sparse' Images.

Then at the bottom he says (who reads down that far these days eh?)

"Until Apple resolves this disk images bug, we strongly recommend that people avoid using APFS-formatted sparse disk images for any purpose with any application."

He's got all the clicks and promotion of his product by the first paragraph.

He could have said "we're dropping support for APFS-formatted Sparse disk images." (my ephasis) but the headline writers may well have passed over it and therefore he'd not get the Interest in (a.k.a. clicks) his product.

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Re: Interesting.

I would say that dropping support for APFS-formatted images, in general, is a good idea until the thing can be reviewed and tested properly. Who knows what other cans of worms are lurking under the surface.

It might be an isolated bug, but given this is backup software, I'd play on the safe side as well and not use APFS images until they have been fixed and thoroughly tested. Anything that is mission critical, like backups, should not rely on known buggy software. If it isn't 100% reliable, neither is your backup!

That is why you use tried and truted technologies for backups and you test them, you test them again and you test them regularly, once they have been implemented. You don't want to wait until you have a disaster, only to find that your backups are actually zero bytes long or corrupted!

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Decades ago I proposed an inexhaustible file system. It was based on the premise of (write, data) without any pesky (write, data, status) worries. The data always went into its repository with 100% reliability. Looks like the idea might have been stolen by Apple. I am contacting my lawyer.

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re: inexhaustable file system

Nah, they didn't copy it from you but the Chinese fakers who sell USB sticks claiming 32Gb when in fact the real size is 512Mb.

Hands up now, how many of us have seen them in real life. Yep, that's a lot.

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Mushroom

Sparse file system?

Some parts are so sparse you can't even locate them!

Still trying to digest that the lower levels of the OS report an error but it just gets ignored. Still, nothing special about writing data these days, is there? Plenty lying around spare in those bucket thingies.

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Mushroom

All I know...

...is when going from OSX to macOS, High Sierra has had me in shock repeatedly with all the bugs I've had to deal with. I've never been so livid over software issues on anything before.

At this point, I honestly don't think Apple can make a sensible minimally acceptable quality software. Having finally acquired another PC and using Linux Mint, the DIFFERENCE is STUNNING. The Latest Linux feels like OSX used to. This was an act of desperation to get everything I need to do off my Mac. With the introduction of High Sierra, my faith in Apple software has been shattered.

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You're storing your files wrong. Just get a bigger disk. Not that big of a problem.

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Holmes

Steven Sinofsky, former president of the Windows group at Microsoft, suggested people are just imagining things.

When you choose to quote someone, you should go for a person with credentials ... Steven's opinion on Windows is probably acceptable, however, what any [former] MS guy thinks of "software stability" is totally irrelevant, in any context I can think of ... I am not saying he is wrong when he compares macOS with Windows (if I understood him correctly), I am saying Steven's opinion here simply does not count.

@Steven, thanks for stating the glaring obvious... you should probably give Linux and/or FreeBSD a try, you'll be surprised, I am sure, to experience ultimate "software stability".

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CCD

Give up on APFS, just use ZFS, it works

We run a mixed Linux / Mac environment, having (happily at the time) migrated from Windows to MacOS in 2003. For the last 15 months we've been storing all data that matters on ZFS filesystems - not just the Linux servers but also on 2nd internal hard disks fitted to our Mac Book Pros and Mac minis (purchased before Apple removed this facility and replaced screws by glue). APFS is very incomplete in comparison with ZFS, and ZFS is incredibly robust and portable.

We're now looking at migrating back from macOS to Windows 10 for some of our applications, primarily because Apple appears to have no concept of (or is that interest in) backward compatibility at the source-code or binary level, and we're fed up with so many things breaking at each major new version of macOS. I have commercial software for Windows that I purchased 15 years ago, that runs perfectly on Windows 10. On macOS I feel lucky if something works for 12 months, and we now defer upgrading to major versions of macOS for around 10 months after they come out, so as to avoid having to do unpaid alpha-testing for Cupertino. Plus Apple keeps trying to force me to change the way I work, by pulling the plug on features and facilities I've relied on for years, no longer offering a 17" laptop, and removing most of the ports that other devices I have would actually connect to, and deliberately slowing down older hardware running newer software.

I accept that if I use Google or Facebook, I'm the product not the customer. But as I pay Apple considerable sums to purchase its hardware, I'd like to ask Tim Cook focus on making what his customers want, rather than endeavouring to make its customers want whatever it has made.

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Boffin

There are other very serious bugs

It appears they have installed another layer in the file system starting around 10.10.

I have a FAT formated USB stick and from the command line this often happens:

$ cd /Volumes/RED8/

$ ls

.

Opps all the files are gone except they aren't. Things like "ls -s | sort" won't work at all sometimes yet ls -s sometimes does. There are plenty of online complaints about this but most seem to think it is related to the shell which it isn't.

I don't know what that extra layer does but I expect it might help protect flash drives from being pulled out without being turned off first or related to their new file system but that is pure speculation. Maybe Apple should have used some of its huge pile of cash to by Larry a new boat and then roll out ZFS properly.

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