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⁠Btrfs has been deprecated in RHEL

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Re: ⁠Btrfs has been deprecated in RHEL

#321

Earlier quoted context omitted.

That's just how raid mirroring works. Now sure why you mention it specifically for btrfs?

No, it isn't. You can run a ZFS VDEV or a Linux mdraid as a single-disk RAID 1 unit until the remaining disk fails. You have an arbitary number of reboots/remounts to fix the problem.

So it turns out there's some nuance here. You can remount it multiple times, as long as you don't write to it, which I was familiar with. The moment you write again and don't explicitly remove the extra volume, you'll lose the ability to mount r/w, which is a pretty bad bug :(

Re: ⁠Btrfs has been deprecated in RHEL

#322

Earlier quoted context omitted.

I think a natural follow-up question is "Why Red Hat does not have engineers to support btrfs?" That is, if the lack of engineers is a symptom, what is the cause? I'm pretty sure, had RH wanted they could either hire or assign engineers to maintain the btrfs code, take care of patches from upstream, etc. So why didn't that happen? I wonder what is your opinion on that. I see a bunch of possibilities (not necessarily…

All this talk about Oracle is just plain stupid. Oracle doesn't control anything, the community does. One core developer still works on Btrfs from Oracle, the vast majority of the contributions come from outside Oracle. Now as to > "Why Red Hat does not have engineers to support btrfs?" You have to understand how most kernel teams work across all companies. Kernel engineers work on what they want to work on, and comp…

> All this talk about Oracle is just plain stupid. Oracle doesn't control anything, the community does. One core developer still works on Btrfs from Oracle, the vast majority of the contributions come from outside Oracle.

FWIW I haven't said anything about Oracle & btrfs ...

>> "Why Red Hat does not have engineers to support btrfs?"

> You have to understand how most kernel teams work across all companies. Kernel engineers work on what they want to work on, and companies hire the people working on the thing the company cares about to make sure they get their changes in.

> This means that the engineers have 95% of the power. Sure you can tell your kernel developer to go work on something else, but if they don't want to do that they'll just go to a different > company that will let them work on what they care about.

> This gives Red Hat 2 options. One is they hire existing Btrfs developers to come help do the work. That's unlikely to happen unless they get one of the new contributors, as all of the seasoned developers are not likely to move. The second is to develop the talent in-house. But again we're back at that "it's hard to tell kernel engineers what to do" problem. If nobody wants to work on it then there's not going to be anybody that will do it.

Sure, I understand many developers have their favorite area of development, and move to companies that will allow them to work on it. But surely some developers are willing to switch fields and start working on new challenges, and then there are new developers, of course. So it's not like the number of btrfs developers can't grow. It may take time to build the team, but they had several years to do that. Yet it didn't happen.

> And then there's the fact that Red Hat really does rely on the community to do the bulk of the heavy lifting for a lot of areas. BPF is a great example of this, cgroups is another good example.

I tend to see deprecation as the last state before removal of a feature. If that's the case, I don't see how community doing the heavy lifting makes any difference for btrfs in RH.

Or are you suggesting they may add it back once it gets ready for them? That's possible, but the truth is if btrfs is missing in RHEL (and derived distributions), that's a lot of users.

I don't know what are the development statistics, but if majority of btrfs developers works for Facebook (for example), I suppose they are working on improving areas important for Facebook. Some of that will overlap with use cases of RHEL users, some of it will be specific. So it likely means a slower pace of improvements relevant to RHEL users.

> Btrfs isn't ready for Red Hat's customer base, nobody who works on Btrfs will deny that fact. Does it make sense for Red Hat to pay a bunch of people to make things go faster when the community is doing the work at no cost to Red Hat?

The question is, how could it get ready for Red Hat's customer base, when there are no RH engineers working on it? Also, I assume the in-house developers are not there only to work on btrfs improvements, but also to investigate issues reported by customers. That's something you can't offload to the community.

I still think RH simply made a business decision, along the lines:

1) The btrfs possibly matters to X% of our paying customers, and some of them might leave if we deprecate it, costing us $Y.

2) In-house team of btrfs developers who would work on it and provide support to customers would cost $Z.

If $Y < $Z, deprecate btrfs.

Re: ⁠Btrfs has been deprecated in RHEL

#323
post #124

More importantly Red Hat has deprecated FCoE in RHEL, which is big news, because at a previous $JOB they went all in on FCoE because it was supposed to be the future.

Ouch? What's the replacement then? ISCSI, or going back to FC? Or is everything cloud something these days? :)

NVME over fabrics.. I guess, the general idea being to run NVME over FC, RCoE, or infiniband.

Given the existing install-base of FC, I'm guessing as people upgrade to the 32/128Gbit adapters they will start to purchase disk's that can support FC-NVME as well. Which will bootstrap the market there.

Although it could go to infiniband as well, if people buy into the converged infiniband/ethernet adapter route.

To soon to tell, but a lot of it will be dependent on which technology does a better job avoiding the "forklift" upgrade problem that FCoE required.

Re: ⁠Btrfs has been deprecated in RHEL

#324

Earlier quoted context omitted.

They brought on Zach right before I left specifically to help with the effort, but he left as well. I can't really speak to Red Hat's overall strategic decisions, but really they have a large local file system team, and a lot of them are xfs developers. You aren't going to convince Dave Chinner he should go work on Btrfs instead of XFS. Unless there's somebody internally that actually wants to work on Btrfs the work…

I'm feeling a subtext here that maybe RH isn't a desired place to work, when I've always imagined the opposite. Is this the case?

Because their talent is XFS instead of Btrfs? I'm feeling a subtext here that maybe Btrfs is an unalloyed good, and that's just not true.

Re: ⁠Btrfs has been deprecated in RHEL

#325
post #202

People are making a bigger deal of this than it is. Since I left Red Hat in 2012 there hasn't been another engineer to pick up the work, and it is _a lot_ of work. For RHEL you are stuck on one kernel for an entire release. Every fix has to be backported from upstream, and the further from upstream you get the harder it is to do that work. Btrfs has to be rebased _every_ release. If moves too fast and there is so muc…

The problem is that Redhat and others are refusing to challenge the norm and break away from the "freeze the release; backport fixes" mantra. Stop backporting fixes. You're forking the codebase. Ship exactly what upstream provides. Teach upstream projects how to do better release engineering if they're abandoning major releases to early or breaking API/ABI in a minor release. Stop backporting fixes. You're forking th…

Not all of us are running systems in their moms basement. "Challenge the norm" is great for people who have nothing to loose from a business perspective.

Re: ⁠Btrfs has been deprecated in RHEL

#326
post #212
post #209

Earlier quoted context omitted.

Which benefits are those? Both synology and qnap have the ability to detect and correct bitrot doing btrfs on top of mdraid.

Being able to have non-symmetric disk topologies with redundancy. I believe that md raid does not support that, while btrfs multi-device does (which is what I think of as one of the really unique features of btrfs -- not even ZFS can handle the sort of disk topologies that btrfs can).

md-raid absolutely supports that and synology has for a long time. They call it "SHR". You simply do raid over disk partitions to enable disks of disparate sizes.

The reason ZFS doesn't support it, and absolutely 0 enterprise storage devices support this is because as the disks fill up, you sacrifice both performance and redundancy. Synology won't even support it on their high-end devices for this very reason. They'll only do it on their devices targeted at home use.

Re: ⁠Btrfs has been deprecated in RHEL

#327
post #147

Earlier quoted context omitted.

If you're on an SSD/MTD/NVMe, you have TRIM, and scrubbing is a no-op no matter what approach you try. You need a spinning HDD for scrubbing to be useful. Here is one way to do simple, secure scrubbing on Linux without any intrusive system changes. It is mildly restrictive, but works. First, you need a small, dedicated partition, but it only needs to be around 16MB or so. Resizing an existing partition down (tune2fs…

You seem to be using a different definition of scrubbing than people talking about filesystems usually use. Scrubbing means to read all the data off a filesystem and compare it against its checksums, so that you are confident nothing has happened to the data (hardware failures, cosmic rays, whatever). ZFS and btrfs have specific scrub commands that do that. There's no scrubbing available for a system which does not k…

OH. You're right. I got the terminology confused with, uh... shredding. Heh.

I actually tried to delete this comment for unrelated reasons shortly after posting it, but was unable to. Now I feel doubly stupid.

Re: ⁠Btrfs has been deprecated in RHEL

#328
post #9

Has anyone here tried bcachefs ( http://bcachefs.org/ ) for some of the same use cases as btrfs? What do people think of its current state?

You'd need to read up on it but the TL;DR i got from previous comments was that previously it was being funded by a company that wasn't 100% aware of the entire situation around it (they used it in their commercial product, management didn't fully understand it was being released as open source, though I also understand they didn't own the rights to the entire code base so basically that was necessary effectively). T…

Oh, they knew it was being released as open source. There was a clear boundary between the open source and the proprietary code - I worked on both. The open source thing was just a convenient excuse for some political bullshit - either that or they thought they could buy out a GPL project and take it proprietary, which is just insane. I mean, half the copyright was Google.

Re: ⁠Btrfs has been deprecated in RHEL

#329
post #281
post #247

Earlier quoted context omitted.

Linux 4.12 introduced dm-integrity, which adds integrity checking at the block device level, so it will work with any file system: https://gitlab.com/cryptsetup/cryptsetup/wikis/DMIntegrity

One good thing about ZFS integrity checking is that when it finds an error it can repair the bit rot from another disk if you have parity or mirroring. Can dm-integrity do that?

Or multiple copies of the data (copies=n property).

Re: ⁠Btrfs has been deprecated in RHEL

#330
post #153

Earlier quoted context omitted.

Good point. I'm using Debian as my Desktop for many years. I don't remember a "botched" system package upgrade in the last 5 years, but i've probably learned over years how to handle dpkg/apt. The atomic updating is a very interesting topic and the reason why i find ostree/guix/nixos very appealing. Note that neither ostree nor guix or nixos make use of filesystem snapshots, afaik. OSTree even documents why it won't…

> So, it's a definitely a nice-to-have, but not something i need, because i can handle dpkg/apt much better then i could handle filesystem internals. I don't think you're seeing my point. You wouldn't have do anything -- it would all be done automatically as long as your file system supports snapshots. BTW, to your "I know how to use dpkg/apt": It's not about knowledge. I could well be said to be at an "advanced" lev…

You're absolutely right. Still, dpkg doesn't support snapshots out of the box. I could fiddle around with it and i suppose i could make a snapshot before running "apt upgrade", but since that never failed for me, i would touch something very stable for little apparent benefit. Let's say Debian 10 will support btrfs snapshots on updates, i'll consider using btrfs for the next installation, but not before.

Did you read the link from the ostree people? Let's pretend Debian 10 offers to choose between OStree-like updates and btrfs snapshots: I'd probably choose OStree and stick to ext4/xfs.

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