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Comment by astrodust | Hacker News Reader

During the 2016 talk on APFS they mentioned it was dropped for various reasons. SSD performance is so ridiculous now that the CPU can't decompress quickly enough, so it'd impair performance. The new notebooks and desktops do 3GB/s read/write, so that's a lot to crunch through in real-time.

I'd suppose if compression is imporatant, do it in your application.

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Transparent compression on FS level is really usefull. HFS+ had that, and all modern FS have that. Be able to compress 1M text files of source code for example.

I'm not sure the compressibility of files is really a factor these days. The largest files on your disk are probably either application software and associated libraries or some kind of media files which are already compressed.

Not many people have a meaningful amount of raw text files sitting around on their system, and those that do can always create a compressed volume if they're so adamant about them being transparently compressed.

Compression is worth it if it saves even a GB on a 128 SSD, or a few hundred MB on a 16GB iPhone.

In an alternate universe where all Macs come with at least 512GB storage, things might be different.

Footnote: Apple still sells 16GB devices: http://www.amazon.in/Apple-iPhone-5s-Space-Grey/dp/B00FXLC9V...

All new devices are 32GB+, so it's less and less of a concern each day, plus the sorts of media files that tend to clog up these devices (photos, video, music) are inherently incompressible.

For 95% of users the space gains from compression in APFS are pretty much irrelevant.

But you can't create a compressed volume with APFS, that's the point isn't it?

You can create a compressed HFS+ volume that's stored on APFS if this is so critically important to you. Otherwise, deal.

Thanks for sharing Apple's rationale, but I disagree. The bottleneck is space, not speed, of SSDs. Few people need a GB per second of read or write more than they need space. If compression gives me even a GB of extra space on a 128GB SSD, I'd take it.

In fact, a 7200RPM hard disc is adequate for me.

I would respectfully argue that you perhaps are the outlier, rather than the people who want more speed out of their direct-attached storage.

Disk speed was the most significant performance bottleneck for years — a point that Apple has repeatedly made in their developer guidelines on performance[1].

I think this is (happily) starting to be less of a concern with these new SSDs capable of 2GB-3GB/second. The 1TB SSD in my 2013 Mac Pro benchmarks at 1GB/sec and I find doubling/tripling that an extremely attractive proposition.

Other than offline backups and archiving systems, I literally haven't used a spinning-magnetic-media storage device since 2013 (and avoided them when possible before that). And I definitely don't plan to ever do so again.

[1]: e.g. https://developer.apple.com/library/content/documentation/Pe...

I wonder if this is a divide between geeks / power users / developers on one hand, who want more speed, and average users, who want more space. Every time someone talks about speed, that statement comes from a geek. By contrast, I have heard non-technical people complain about insufficient space on their 128GB Macbooks, but not about the speed. Maybe my sample size isn't big enough. I don't know.

When you said that people want more speed out of their storage, sure, we all want it in the abstract, but did you mean even at the cost of having less space for a higher price?

My iMac's Fusion Drive failed, in the sense of not using the SSD at all, and I didn't notice much difference except in specific situations, like booting, app startup and swapping. On the whole, I wasn't any less productive or more irritated with a hard disc. A small screen, a slower Internet connection and having to move data back and forth to external hard discs are a bigger pain for me than the speed of a hard disc, assuming it's 7200 RPM.

You're in the minority and that minority is shrinking. APFS isn't being designed for HDDs, support for them is more of a concession than a concern, as the future is, clearly, SSD or better.

SSDs already have higher capacities than any HDD, and soon their price will drop down to parity and then below as SSD gains continue to outpace those in the HDD domain.

We're in the transition period here where, for the next few years, SSD space will still be at a premium vs. HDD. Beyond that the SSD will offer vastly more storage than you could possibly need at a cost you can afford.

In the interim if compression gives you an extra GB of space then make a compressed volume and mount that. It's fully under your control.

Maybe you're right that in a few years, I'll be able to buy a 6TB SSD for the $200 I'd pay for a hard disc today, but speaking as a user about to buy a computer, I want one that works great today. Which means worrying less about filling up my paltry 128GB SSD.

The other, non-technical, solution is for Apple to make 512GB SSDs standard :) But Apple is going in the other direction, introducing a 128GB SSD.

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