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Comment by DiabloD3 | Hacker News Reader

Oracle discontinued BTRFS development when they bought Sun, merged the ZFS and BTRFS team, and then fired anyone on the BTRFS team that didn't have ZFS experience.

BTRFS is basically on maintenance mode, and no one at Redhat/IBM or Ubuntu has any interest in keeping it alive. Anyone that requires HA services will not be using BTRFS.

Redhat ships with XFS as the default file system, Ubuntu ships with Ext4 as default with heavy install-time ZFS support for enterprise storage, and BTRFS is no longer being spoken of by anyone as a potential Ext5 candidate.

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90% of this is wrong. Oracle bought Sun in 2009, and continued to make substantial contributions for years after that, and they still have developers actively contributing to Btrfs. The idea they merged the ZFS and Btrfs teams is absurd, the two file systems are nothing alike either in terms of design, on disk format, or code base.

Btrfs is on maintenance mode? Based on what evidence? There's 1k-2k commits per kernel cycle. There are dozens of developers actively working on it. Facebook is certainly using it in production for high availability in concert with Gluster FS, they're also using Btrfs almost exclusively with Tupperware, their containerization service.

Red Hat has quite a lot of device mapper, LVM, and XFS developers so it makes sense for them to work on storage solutions that continue to build on that. And Red Hat hasn't been significantly contributing to Btrfs for many years now, so their lack of interest isn't new and hasn't affected Btrfs development.

>The idea they merged the ZFS and Btrfs teams is absurd, the two file systems are nothing alike either in terms of design, on disk format, or code base.

You've never seen the same team working on two very separate code bases or products?

I have no idea if the btrfs and zfs teams at Oracle were merged, but I don't know that "they are two separate products" is actually a real argument that they weren't. Product teams working on separate things get merged all the time.

I've seen a tiny handful of developers juggle more than one file system at a time. They're that complicated. I'm familiar with most of the Btrfs developers and can't think of a single one who works on ZFS; the most active developers when asked about it quite a few years ago on the Btrfs development list said they were unfamiliar with ZFS and it wasn't used as a guide for Btrfs.

You can track developers through their git commits, and you'll see even when they change companies, they almost invariably keep working on the same filesystem they were before the move. Which is why the idea that Red Hat has no one working on Btrfs, means they want to see it go away is not what's going on at all. They have a lot of other developers already, who'd lose years becoming familiar with Btrfs (or ZFS for that matter). So you're going to see them build on what they already are familiar with, rather than moving laterally to a filesystem technology they're not familiar with.

Is it in maintenance mode? Chris Mason (the main btrfs developer) works for Facebook now and Facebook uses btrfs on "millions of servers" (source: https://code.fb.com/open-source/linux/).

Facebook's usage of it is very specific, but as you mentioned, Chris Mason (who used to also work at Oracle on their BTRFS team before Oracle dumped BTRFS) is there in-house to make sure it is smooth.

However, I'm pretty sure if I boiled the commit history down for the kernel, most of Facebook's commits would be Flashcache, and not BTRFS.

What I forgot, though, is SuSE supports it as their enterprise FS of choice, which is maybe more important than Facebook.

Yes. It's important to recognize that there's a big difference in one's willingness to adopt a technology if its creator is on staff. Chris Mason's full-time job is to make sure the thing he built works well for his employer.

If you work some place that doesn't have that kind of luxury, perhaps a little extra conservatism is warranted before you go deploying across "millions of servers".

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