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Comment by AsyncAwait | Hacker News Reader

> Linux is still catching up with btrfs...

ZFS is available on Linux if you want it, in fact FreeBSD is basing its support for ZFS on it.

For a mainline option, am personally holding out hope for bcachefs, rather than btrfs.

I think the way btrfs manages physical volumes is better. With btrfs, I can slowly buy drives of different capacities and add them to the file system one by one. I don't have to plan ahead of time like traditional RAID and ZFS setups. This is excellent for home data storage!

The only thing that holds it back is the lack of proper parity support. Anyone has an update on that? The kernel wiki says it still has problems...

You may wish to check out the new dRAID mechanism that recently got committed:

* https://www.youtube.com/watch?v=jdXOtEF6Fh0

* https://openzfs.github.io/openzfs-docs/Basic%20Concepts/dRAI...

regarding raid5/6 on btrfs - in this recent message [1] Zygo Blaxell writes:

> Not much has changed for raid5/6 since 2014, other than the introduction > of raid1c3 for metadata in 2019 to make filesystem with raid6 data usable. > Almost all of the bugs from 2014 still exist today. Developers have > been fixing more severe and less avoidable bugs in the meantime.

[1]: https://www.spinics.net/lists/linux-btrfs/msg107268.html

Also, worth mentioning another email from same author with guidelines for users running btrfs raid5 array: https://lore.kernel.org/linux-btrfs/20200627032414.GX10769@h...

It seems like btrfs will gain a lot of traction, considering that Facebook invest a lot in it and it's the default FS in Fedora now.

Maybe. But I wonder if btrfs has been tainted as 'too unreliable' at this point, whether true or not.

I first heard about Btrfs over ten years ago: what's taking it so long to 'gain traction'?

My guess is bugs. Early on they had some serious bugs that lost people data. So the project gained this reputation of not being production-ready which meant that only people interested in playing with a new filesystem were using it. And btrfs has always been brought up alongside zfs which has been stable and mature for decades. As far as I can tell the only advantage btrfs has over zfs is the license. Outside of that, what does it offer that zfs does not? (That’s a serious question, I haven’t kept up with it because I’m a happy zfs user.)

> what does btrfs offer that zfs does not?

As @matheusmoreira mentioned - you can use harddisks of unequal size. I.e. three disks of 4+3+3 Tb in RAID1 will happily give you 5 Tb of usable space. AFAIK, no other filesystem can do that.

Quoting @matheusmoreira further:

> I can slowly buy drives of different capacities and add them to the file system one by one. I don't have to plan ahead of time like traditional RAID and ZFS setups. This is excellent for home data storage!

The new dRAID mechanism in ZFS may help with this:

* https://www.youtube.com/watch?v=jdXOtEF6Fh0

How? I don't see how it makes ZFS more flexible. Users still need to have every storage device installed on the computer before creating the RAID configuration. They can't start with the drives they already have and then add more drives over time. At least not without essentially recreating the array from scratch.

It's been perfectly stable since years for me. Not using Raid 5/6 of course!

Are you using snapshots? qgroups (which you have to enable to see snapshot space utilization)?. I've had bad experiences with them on btrfs.

not OP, but using btrfs for 0.5 year with snapshots, snapper (which creates snapshots every hour) on NVMe under Arch. Haven't noticed any issues yet - qgroups are disabled, and snapper config decreased to have no more than 20 snapshots.

Ya, I was using snapper but didn't restrict the number of snapshots so I probably had more than 20

I use zfs now and have many, many, more than 20 snapshots without issue.

I wasn't using a nvme drive with btrfs, it was a sata ssd. So perhaps the higher io ops or lower latency also helps.

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