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Linus: Don't Use ZFS

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Re: Linus: Don't Use ZFS

#141
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…

> And I'm not at all interested in some "ZFS shim layer" thing either If there is no "approved" method for creating Linux drivers under licenses other than the GPL, that seems like a major problem that Linux should be working to address. Expecting all Linux drivers to be GPL-licensed is unrealistic and just leads to crappy user experiences. nVidia is never going to release full-featured GPL'd drivers, and even corpor…

>[...] that seems like a major problem that Linux should be working to address [...] Why are all drivers expected to use the GPL?

Vendors are expected to merge their drivers in mainline because that is the path to getting a well-supported and well-tested driver. Drivers that get merged are expected to use a GPL2-compatible license because that is the license of the Linux kernel. If you're wondering why the kernel community does not care about supporting an API for use in closed-source drivers, it's because it's fundamentally incompatible with the way kernel development actually works, and the resulting experience is even more crappy anyway. Variations of this question get asked so often that there are multiple pages of documentation about it [0] [1].

The tl;dr is that closed-source drivers get pinned to the kernel version they're built for and lag behind. When the vendor decides to stop supporting the hardware, the drivers stop being built for new kernel versions and you can basically never upgrade your kernel after that. In practice it means you are forced to use that vendor's distro if you want things to work properly.

>[...] nVidia is never going to release full-featured GPL'd drivers.

All that says to me is that if you want your hardware to be future-proof, never buy nvidia. All the other Linux vendors have figured out that it's nonsensical to sell someone a piece of hardware that can't be operated without secret bits of code. If you ever wondered why Linus was flipping nvidia the bird in that video that was going around a few years ago... well now you know.

[0]: https://www.kernel.org/doc/html/latest/process/kernel-driver...

[1]: https://www.kernel.org/doc/html/latest/process/stable-api-no...

Re: Linus: Don't Use ZFS

#142
Perhaps if one wanted to use ZFS they should just use a kernel that supports it?

ZFS is certainly "nice to have" on desktop, but the main use case is going to be servers and NAS. You can use BSD there, it won't bite.

Re: Linus: Don't Use ZFS

#143
post #138

He's not wrong. ext4 is actually maintained. This matters. ZFS hasn't kept up with SSDs. ZFS partitions are also almost impossible to resize, which is a huge deal in today's world of virtualized hardware. Honestly Linus's attitude is refreshing. It's a sign that Linux hasn't yet become some stiff design-by-committee thing. One guy ranting still calls the shots. I love it. Protect this man at all costs.

"ZFS hasn't kept up with SSDs."

What does that mean?

Re: Linus: Don't Use ZFS

#144
post #22

Earlier quoted context omitted.

Same, for at least 6 years in a 4 drive zraid array. It always reads and writes at full gigabit ethernet speeds and I haven't had any downtime other than maintaining FreeBSD updates which are trivial even when going from 10.x to 11 to 12.

Same here (4-drive raidz for many years), though I do have an issue where deleting large files (~1 GB) takes around a minute and nobody seems to know why (I have plenty free space and RAM)...

do you have lots of snapshots? every snapshotting FS I've worked with has really slow deletes, especially when the volume is near capacity.

Re: Linus: Don't Use ZFS

#145
post #89

Until I have a viable alternative that gives me snapshotting (so I can make consistent backups), that advice is worthless to me.

in the application-level, snapshotting is not a way to do "consistent backup"s . consistent backup is a backup with a planned or known state when "restore"ing.

Re: Linus: Don't Use ZFS

#146
post #138

He's not wrong. ext4 is actually maintained. This matters. ZFS hasn't kept up with SSDs. ZFS partitions are also almost impossible to resize, which is a huge deal in today's world of virtualized hardware. Honestly Linus's attitude is refreshing. It's a sign that Linux hasn't yet become some stiff design-by-committee thing. One guy ranting still calls the shots. I love it. Protect this man at all costs.

> ZFS partitions are also almost impossible to resize

I'm not sure you've actually used ZFS very much as any way I can see you could be meaning this, it is actually pretty straightforward and simple to resize partitions with ZFS pools and volumes within ZFS pools.

For example, if you mean that you have a root zpool on a device using only half the device, you just have to resize the partition and then turn on `autoexpand` for the pool.

Re: Linus: Don't Use ZFS

#147
post #138

He's not wrong. ext4 is actually maintained. This matters. ZFS hasn't kept up with SSDs. ZFS partitions are also almost impossible to resize, which is a huge deal in today's world of virtualized hardware. Honestly Linus's attitude is refreshing. It's a sign that Linux hasn't yet become some stiff design-by-committee thing. One guy ranting still calls the shots. I love it. Protect this man at all costs.

"ZFS hasn't kept up with SSDs." What does that mean?

That they've never used SSDs for a ZIL or a zpool, I would wager.

Re: Linus: Don't Use ZFS

#148

Earlier quoted context omitted.

>stop wasting money on BTRFS You're saying they should stop supporting a project that was considered stable by the time the other started being developed. Why do that? What makes Bcachefs a better choice?

Take a cursory look into both codebases, the stability of the every feature at launch and on maintenance. It's not hard to see BTRFS is a doomed project. Bcachefs is more like PostgreSQL, the developer doesn't add features until he has a solid design that's well thought out. Hence why he hasn't implemented snapshots. I don't think too many people consider it stable enough for production, either. (Unless you count a v…

If you are on BTRFS and you encounter an unrecoverable bug (which seems to be reasonably common), the developers will most likely recommend you wipe the drive and restore from backups (because you had backups, right?)

Even if the data is still on the drive and a bugfix would make the filesystem recoverable again, they don't have the time/knowledge/resources to untangle that codebase and make fixes. Even BTRFS developers don't trust the filesystem with their own data.

If you are on Bcachefs and you encounter an unrecoverable bug, the developer will ask for some logs, or reproduction steps, or potentially even remote debugging access to your corrupt filesystem.

And then he will fix the bug, releasing a new version that can read/repair your filesystem. He knows his codebase like the back of hand.

In my research, I couldn't find any examples of someone actually losing data due to Bcachefs. All the bugs appeared to be "data has been written to drive, but bug prevented reading"

While I would still hesitate to trust Bcachefs, I would trust it way more than BTRFS.

Re: Linus: Don't Use ZFS

#149
post #137

Earlier quoted context omitted.

Can you expand? I'm no expert - use linux daily but have always just used distro default file system. Linus' reasons for not integrating seems pretty sensible to me. Oracle certainly has form on the litigation front.

Linus' reasons for not integrating ZFS are absolutely valid and it's no doubt that ZFS can never be included in the mainline kernel. There's absolutely no debate there. However the person he is replying to was not actually asking to have ZFS included in the mainline kernel. As noted above, that could never happen, and I believe that Linus is only bringing it up to deflect from the real issue. What they were actually…

>This is done strictly for political reasons and has no known legal basis as far as I'm aware.

let me stop you right there. This being "Oracle," and its litigious nature, how can you truly be aware or sure?

Linus is literally saying there is a legal basis.

Re: Linus: Don't Use ZFS

#150
post #35
post #7

Earlier quoted context omitted.

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

Here are his reasons for generally avoiding ZFS from what I consider most important to least. - The kernel team may break it at any time, and won't care if they do. - It doesn't seem to be well-maintained. - Performance is not that great compared to the alternatives. - Using it opens you up to the threat of lawsuits from Oracle. Given history, this is a real threat. (This is one that should be high for Linus but not…

> - Performance is not that great compared to the alternatives.

CoW filesystems do trade performance for data safety. Or did you mean there are other _stable/production_ CoW filesystems with better performance? If so, please do point them out!

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