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ZFS: Apple's new filesystem that wasn't (2016)

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Re: ZFS: Apple's new filesystem that wasn't (2016)

#91
post #2

Besides the licensing issue, I wonder if optimizing ZFS for low latency + low RAM + low power on iPhone was an uphill battle or if it’s easy. My experiencing running ZFS years ago was poor latency and large RAM use with my NAS, but that hardware and drive configuration was optimized for low $ per gb stored and used parity stuff.

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Re: ZFS: Apple's new filesystem that wasn't (2016)

#92
post #70
post #36

Earlier quoted context omitted.

Yeah I think if it hadn’t been for the combination of Oracle and CDDL, Red Hat would have been more interested in for Linux. As it was they basically went with XFS and volume management. Fedora did eventually go with btrfs but dints know if there are are any plans for copy-on-write FS for RHEL at any point.

RedHat’s policy is no out of tree kernel modules, so it would not have made a difference.

It’s not like Red Hat had/has no influence over what makes it into mainline. But the options for copy on write were either relatively immature or had license issues in their view.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#93

Earlier quoted context omitted.

We had those things at work as fileservers, so no containers or anything fancy. Sun salespeople tried to sell us the idea of "zfs filesystems are very cheap, you can create many of them, you don't need quota" (which ZFS didn't have at the time), which we tried out. It was abysmally slow. It was even slow with just one filesystem on it. We scrapped the whole idea, just put Linux on them and suddenly fileserver perform…

I had a combination uh-oh/wow! moment back in those days when the hacked up NFS server I built on a Dell with Linux and XFS absolutely torched the Solaris and UFS system we'd been using for development. Yeah, it wasnt apples to apples. Yes, maybe ZFS would have helped. But XFS was proven at SGI and it was obvious that the business would save thousands overnight by moving to Linux on Dell instead of sticking with Sun…

ZFS probably wouldn't have helped. One of my points is, ZFS was slower than UFS in our setup. And both where slower than Linux on the same hardware.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#94
post #89

Earlier quoted context omitted.

Licensing concerns that prevent distros from using ZFS will sooner or later also have adverse effects on end users. Actually those effects are already there: The constant need to adapt a large patchset to the current kernel, meaning updates are a hassle. The lack of packaging in distributions, meaning updates are a hassle. And the lack of integration and related tooling, meaning many features can not be used (like a/…

Unlike other out of tree filesystems such as Reiser4, the ZFS driver does not patch the kernel sources.

That is due to licensing reasons, yes. It makes maintaining the codebase even more complicated because when the kernel module API changes (which it very frequently does) you cannot just adapt it to your needs, you have to work around all the new changes that are there in the new version.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#95

Earlier quoted context omitted.

Both are imho linked to "offline desktop use cases are not important anymore". Both companies saw their future gains elsewhere, in internet-related functions and what became known as "cloud". No need to have a fancy, featurefull and expensive filesystem when it is only to be used as a cache for remote cloud stuff.

Exactly this. The business case for providing a robust desktop filesystem simply doesn’t exist anymore. 20 years ago, (regular) people stored their data on computers and those needed to be dependable. Phones existed, but not to the extent they do today. Fast forward 20 years, and many people don’t even own a computer (in the traditional sense, many have consoles). People now have their entire life on their phones, ba…

Workstation use cases exist. Data archival is not the only application of file systems.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#96

I wonder what ZFS in the iPhone would've looked like. As far as I recall, the iPhone didn't have error correcting memory, and ZFS is notorious for corrupting itself when bit flips hit it and break the checksum on disk. ZFS' RAM-hungry nature would've also forced Apple to add more memory to their phone.

ZFS detects corruption. A very long ago someone named cyberjock was a prolific and opinionated proponent of ZFS, who wrote many things about ZFS during a time when the hobbyist community was tiny and not very familiar with how to use it and how it worked. Unfortunately, some of their most misguided and/or outdated thoughts still haunt modern consciousness like an egregore. What you are probably thinking of is the pro…

To me, the most implausible thing about ZFS-without-ECC doomsaying is the presumption that the failure mode of RAM is a persistently stuck bit. That's way less common than transient errors, and way more likely to be noticed, since it will destabilize any piece of software that uses that address range. And now that all modern high-density DRAM includes on-die ECC, transient data corruption on the link between DRAM and CPU seems overwhelmingly more likely than a stuck bit.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#97

Earlier quoted context omitted.

ZFS detects corruption. A very long ago someone named cyberjock was a prolific and opinionated proponent of ZFS, who wrote many things about ZFS during a time when the hobbyist community was tiny and not very familiar with how to use it and how it worked. Unfortunately, some of their most misguided and/or outdated thoughts still haunt modern consciousness like an egregore. What you are probably thinking of is the pro…

> Hell, I’ve never even had bad ram. To what degree can you separate this claim from "I've never noticed RAM failures"?

It isn't hard to run memtest on all your computers, and that will catch the kind of bad RAM that the aforementioned doomsday scenario requires.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#98
post #40

Earlier quoted context omitted.

Linux or FreeBSD developers are free to adopt ZFS as their primary file systems. But it appears that practical benefits are not really evident to most users.

That's called marketing. Give it a snazzy name, like say "TimeMachine" and users will jump on it. Also, ZFS has a bad name within the Linux community due to some licensing stuff. I find that most BSD users don't really care about such legalese and most people I know that run FreeBSD are running ZFS on root. Which works amazingly well I might add. Especially with something like sanoid added to it, it basically does th…

>I find that most BSD users don't really care about such legalese and most people I know that run FreeBSD are running ZFS on root.

What a weird take. BSD's license is compatible with ZFS, that's why. "Don't really care?" Really? Come on.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#99
post #40

Earlier quoted context omitted.

Linux or FreeBSD developers are free to adopt ZFS as their primary file systems. But it appears that practical benefits are not really evident to most users.

That's called marketing. Give it a snazzy name, like say "TimeMachine" and users will jump on it. Also, ZFS has a bad name within the Linux community due to some licensing stuff. I find that most BSD users don't really care about such legalese and most people I know that run FreeBSD are running ZFS on root. Which works amazingly well I might add. Especially with something like sanoid added to it, it basically does th…

Time Machine was released 17 years ago, and I wish Windows had anything that good. And they're on their 3rd backup system since then.

Re: ZFS: Apple's new filesystem that wasn't (2016)

#100
post #68
post #31

Earlier quoted context omitted.

ZFS was developed in Solaris, and at the time we were mostly selling SPARC systems. That changed rapidly and the biggest commercial push was in the form of the ZFS Storage Appliance that our team (known as Fishworks) built at Sun. Those systems were based on AMD servers that Sun was making at the time such as Thumper [1]. Also in 2016, Ubuntu leaned in to use of ZFS for containers [2]. There was nothing that specific…

> There was nothing that specific about Solaris that made sense for ZFS, and even less of a connection to the SPARC architecture. Although it does not change the answer to the original question, I have long been under the impression that part of the design of ZFS had been influenced by the Niagara processor. The heavily threaded ZIO pipeline had been so forward thinking that it is difficult to imagine anyone devising…

I don’t recall that being the case. Bonwick had been thinking about ZFS for at least a couple of years. Matt Ahrens joined Sun (with me) in 2001. The Afara acquisition didn’t close until 2002. Niagara certainly was tantalizing but it wasn’t a primary design consideration. As I recall, AMD was head and shoulders above everything else in terms of IO capacity. Sun was never very good (during my tenure there) at coordination or holistic strategy.
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