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Linus: Don't Use ZFS

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Re: Linus: Don't Use ZFS

#41

Post by lmilcin »

Hamuko wrote: post #7
Jonnax wrote: post #4

Here's his reasoning: "honestly, there is no way I can merge any of the ZFS efforts until I get an official letter from Oracle that is signed by their main legal counsel or preferably by Larry Ellison himself that says that yes, it's ok to do so and treat the end result as GPL'd. Other people think it can be ok to merge ZFS code into the kernel and that the module interface makes it ok, and that's their decision. But…

That's his reasoning for not merging ZFS code, not for generally avoiding ZFS.

The problem with ZFS is that it isn't part of Linux kernel.

Linux project maintains compatibility with userspace software but it does not maintain compatibility with 3rd party modules and for a good reason.

Since modules have access to any internal kernel API it is not possible to change anything within kernel without considering 3rd party code, if you want to keep that code working.

For this reason the decision was made that if you want your module to work you need to make it part of Linux kernel and then if anybody refactors anything they need to consider modules they would be affecting by the change.

Not allowing the module to be part of the kernel is a disservice to your user base. While there are modules like that that are maintained moderately successfully (Nvidia, vmware, etc.) this is all at the cost of the user and userspace maintainers who have to deal with it.

Re: Linus: Don't Use ZFS

#42

Post by Seenso »

Covzire wrote: post #13
Hamuko wrote: post #7

Earlier quoted context omitted.

That's his reasoning for not merging ZFS code, not for generally avoiding ZFS.

Relevant bits: "Don't use ZFS. It's that simple. It was always more of a buzzword than anything else, I feel, and the licensing issues just make it a non-starter for me. The benchmarks I've seen do not make ZFS look all that great. And as far as I can tell, it has no real maintenance behind it either any more, so from a long-term stability standpoint, why would you ever want to use it in the first place?"

> The benchmarks I've seen do not make ZFS look all that great.

The thing about ZFS that actually appeals to me is how much error-checking it does. Checksums/hashes are kept of both data and metadata, and those checksums are regularly checked to detect and fix corruption. As far as I know it (and filesystems with similar architectures) are the only ones that can actually protect against bit rot.

https://github.com/zfsonlinux/zfs/wiki/Checksums

> And as far as I can tell, it has no real maintenance behind it either any more, so from a long-term stability standpoint, why would you ever want to use it in the first place?"

It has as much maintenance as any open source project: http://open-zfs.org/. IIRC, it has more development momentum behind it than the competing btrfs project.

Re: Linus: Don't Use ZFS

#43

Post by reacharavindh »

fgonzag wrote: post #25
reacharavindh wrote: post #10

As a heavy user of ZFS and Linux, what else is there that even comes close to what ZFS offers? I want cheap and reliable snapshots, export & import of file systems like ZFS datasets, simple compression, caching facilities(like SLOG and ARC) and decent performance.

Bcachefs is probably the only thing that will get there. The codebase is clean and we'll mantained, built from solid technology (bcache) and will include most of the ZFS niceties. I just wish more companies would sponsor de project and stop wasting money on BTRFS

Yes, I’m eagerly waiting for Bcachefs to get there at some point, but it is several years away (rightly so, because it is hard and the developer is doing an amazing job) if my understanding of its state is correct.

I have heard of durability issues with btrfs, and do not want to touch it if it fails with its primary job.

Re: Linus: Don't Use ZFS

#44

Post by voltagex_ »

rleigh wrote: post #24
Covzire wrote: post #13

Earlier quoted context omitted.

Relevant bits: "Don't use ZFS. It's that simple. It was always more of a buzzword than anything else, I feel, and the licensing issues just make it a non-starter for me. The benchmarks I've seen do not make ZFS look all that great. And as far as I can tell, it has no real maintenance behind it either any more, so from a long-term stability standpoint, why would you ever want to use it in the first place?"

Not sure where that belief comes from. But it might be that many benchmarks are naive and compare it against other filesystems in single-disc setups with zero tuning. Since its metadata overheads are higher, it's definitely slower in this scenario. However, put a pool onto an array of discs and tune it a little, and the performance scales up and up leaving all Linux-native filesystems, and LVM/dm/mdraid, well behind.…

Have you got any info on how to do the required tuning that's geared towards a home NAS?

Re: Linus: Don't Use ZFS

#45

Post by __jal »

Covzire wrote: post #13
Hamuko wrote: post #7

Earlier quoted context omitted.

That's his reasoning for not merging ZFS code, not for generally avoiding ZFS.

Relevant bits: "Don't use ZFS. It's that simple. It was always more of a buzzword than anything else, I feel, and the licensing issues just make it a non-starter for me. The benchmarks I've seen do not make ZFS look all that great. And as far as I can tell, it has no real maintenance behind it either any more, so from a long-term stability standpoint, why would you ever want to use it in the first place?"

Linus is just wrong as far as maintenance, as a look at the linux-zfs lists would show.

From my perspective, it has no real competitor under linux, which is why I use it. I don't consider brtfs mature enough for critical data. (Others can reasonably disagree, I have intentionally high standards for data durability.)

Aside from legal issues, he's talking out of his ass.

Re: Linus: Don't Use ZFS

#46

Post by m0zg »

blibble wrote: post #2

I'll give up Linux on my servers before I give up ZFS especially so given the recent petulant attitude that broke API compatibility in the LTS branch just to spite the ZFS developers: https://news.ycombinator.com/item?id=20186458 compete honestly on technical merit, rather than pulling dirty tricks that you'd expect of Oracle or 1990's MS

Pretty much my view as well. If Linux becomes incompatible with ZFS in any way, I'll switch to FreeBSD.

That said, after the Oracle Java debacle, I can see why Linus would not be receptive towards merging ZFS into the kernel. I just wish he argued the point on legal issues alone instead of making up stories about non-existent technical flaws in ZFS. The whole thing is basically a work of art. Oracle should consider GPL-ing it and integrating it into Linux directly.

Re: Linus: Don't Use ZFS

#47

Post by unethical_ban »

lmilcin wrote: post #41
Hamuko wrote: post #7

Earlier quoted context omitted.

That's his reasoning for not merging ZFS code, not for generally avoiding ZFS.

The problem with ZFS is that it isn't part of Linux kernel. Linux project maintains compatibility with userspace software but it does not maintain compatibility with 3rd party modules and for a good reason. Since modules have access to any internal kernel API it is not possible to change anything within kernel without considering 3rd party code, if you want to keep that code working. For this reason the decision was…

Parent updated their post and my comment is no longer relevant.

Re: Linus: Don't Use ZFS

#48

Post by znpy »

bayindirh wrote: post #39
rkagerer wrote: post #21

Earlier quoted context omitted.

He also feels ZFS "was always more of a buzzword than anything else". Yikes.

Honestly, I wouldn't bash him for this comment. Not everyone runs a 10+ TB array at their home for storage and backup purposes. ZFS doesn't primarily target single disks and small arrays anyway. :)

people probably will, in a few years.

rotational disks are getting cheaper and cheaper, 10TB disks in two years might cost as little as 2TB disks today (i got a 2TB disk for like 50€ off Amazon).

Re: Linus: Don't Use ZFS

#49

Post by shawnz »

Jonnax wrote: post #4

Here's his reasoning: "honestly, there is no way I can merge any of the ZFS efforts until I get an official letter from Oracle that is signed by their main legal counsel or preferably by Larry Ellison himself that says that yes, it's ok to do so and treat the end result as GPL'd. Other people think it can be ok to merge ZFS code into the kernel and that the module interface makes it ok, and that's their decision. But…

This is nonsense. The problem is not getting ZFS bundled with Linux like he is implying here. The problem is how Linux artificially restricts what APIs your module is able to access based on the license, so you wouldn't be able to use ZFS even by your own prerogative like he is suggesting.

He is claiming that it comes down to the user's choice, which would be just fine if that were true. The only problem here is that Linux has purposely taken steps to hinder that choice.

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