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Linux 5.10 BTRFS performance regression

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Re: Linux 5.10 BTRFS performance regression

#81

Post by tuldia »

gregkh wrote: post #56
esgwpl wrote: post #14

This version has got to be the worst kernel released in a while in terms of regression, from AMDGPU null pointer dereference crash[0] to f2fs data corruption bug[1] and now this. Fixes for these are on their way as far as I can tell but since the stable team are probably on Christmas vacation it might take a while. [0] https://bbs.archlinux.org/viewtopic.php?pid=1943906#p1943906 [1] https://bugzilla.kernel.org/show_b…

I get a vacation? Hah!

Every software has bugs, and is easier to criticize than to help. Don't focus on the negativity of HN and keep it up!

Thanks for your hard work, Greg!

Re: Linux 5.10 BTRFS performance regression

#82

Post by yjftsjthsd-h »

thomaszander wrote: post #12
throwii wrote: post #6

Earlier quoted context omitted.

Why does btrfs have those issues compared to other filesystems? I'd love to use btrfs too. Note that I deeply respect people who can write such complicated code, which I couldn't. Would Rust solve the non-speed issues? Rust-in-kernel discussion from August: https://lwn.net/Articles/829858/

> Why does btrfs have those issues compared to other filesystems? As someone that has built infrastructure on BtrFS for years, the scary stories are mostly just hot air and the stability of other filesystems is really not significantly better. Bugs like this happen, this is why Linus releases many release-candiates every kernel, this one got through as 10 was a rather massive kernel and there were several regressions…

> As someone that has built infrastructure on BtrFS for years, the scary stories are mostly just hot air and the stability of other filesystems is really not significantly better.

I've lost 2 root filesystems to btrfs, on a laptop with only 1 drive (read: not even using RAID). Have you considered that you're just lucky?

Re: Linux 5.10 BTRFS performance regression

#83

Post by yjftsjthsd-h »

NavinF wrote: post #72
solarkraft wrote: post #48

Earlier quoted context omitted.

It's not as compelling to write about positive experiences. The main competitor to btrfs is zfs, which is harder to set up, arguably more complex and has licensing issues so you can't really ship things with it built in. I like zfs on my server, but am also happy with btrfs on my laptop.

ZFS is not harder to set up imo. It's as easy as `sudo apt install zfsutils-linux` and `zpool create poolname raidz2 disk1 disk2 disk3` I've been bitten by btrfs back when it was the new hot FS, so I'll just stick to ZFS until a distributed (multiple machines) equivalent of ZFS comes along.

> until a distributed (multiple machines) equivalent of ZFS comes along.

Ceph?

Re: Linux 5.10 BTRFS performance regression

#84

Post by rincebrain »

xaduha wrote: post #77
ksec wrote: post #75

Earlier quoted context omitted.

>Always was told that you can't beat hardware RAID Is that new? I have always been told to avoid hardware raid when possible.

There were pseudo hardware RAID controllers aplenty, that's what you were told to avoid.

Not necessarily the case - avoiding pseudo-HW RAID controllers can be reasonable advice, and may have been what was said, but some of us were explicitly told to avoid real hardware RAID controllers, period, for the reasons that have been listed upthread. [1]

It's great that you've had good experiences with this particular hardware RAID controller and are recommending it to others, but it's also the case that there are legitimate reasons to avoid all hardware RAID cards in some setups.

[1] - https://news.ycombinator.com/item?id=25518122

Re: Linux 5.10 BTRFS performance regression

#86

Post by zaarn »

kefyras wrote: post #80
zaarn wrote: post #46

Earlier quoted context omitted.

One thing Btrfs somewhat promised was mixed disk RAIDs. Ie, having a 2TB disk and a 1TB disk and being able to say "keep 2 copies of any data in this subvolume" and "keep only 1 copy in this subvolume". I'm currently on Bcachefs, which has erasure coding with similar promises and works better for me. ZFS is more rigid, I have to have all matched disks for best performance, plus RAM unless I like bad performance (I do…

> but ZFS doesn't like living on a partitioned disk nearly as much. Don't know how true is this, since it's not even possible to create a zpool on the whole unpartitioned device on linux. It automatically creates GPT label with zfs and a small efi partition.

That is true, but I suspect that only happens to protect the zpool against tools like the Windows Repair Install (which likes to attempt repairs on disks without GPT label). Using ZFS on a partition inside a GPT disk tends to lead to a few quirky behaviours, like for example ZFS not always reporting correct SMART data of the device.

Re: Linux 5.10 BTRFS performance regression

#87

Post by rincebrain »

MisterTea wrote: post #36
ahachete wrote: post #24

Earlier quoted context omitted.

Is any software ever finished? ZFS has been quite feature-full and production ready for more than a decade... why do you think it is not finished?

> Is any software ever finished? Yes. When it does what it advertises, properly.

OpenZFS, in general, does what it advertises fairly well, and does not advertise features it does not possess.

In what way has your experience differed?

Re: Linux 5.10 BTRFS performance regression

#88

Post by xaduha »

rincebrain wrote: post #84
xaduha wrote: post #77

Earlier quoted context omitted.

There were pseudo hardware RAID controllers aplenty, that's what you were told to avoid.

Not necessarily the case - avoiding pseudo-HW RAID controllers can be reasonable advice, and may have been what was said, but some of us were explicitly told to avoid real hardware RAID controllers, period, for the reasons that have been listed upthread. [1] It's great that you've had good experiences with this particular hardware RAID controller and are recommending it to others, but it's also the case that there ar…

Well, what are your experiences exactly?

Re: Linux 5.10 BTRFS performance regression

#89

Post by gregkh »

tuldia wrote: post #81
gregkh wrote: post #56

Earlier quoted context omitted.

I get a vacation? Hah!

Every software has bugs, and is easier to criticize than to help. Don't focus on the negativity of HN and keep it up! Thanks for your hard work, Greg!

If people don't report bugs, we don't know they are there as it "works for me!".

This isn't "negativity", this is people not understanding how the process works :)

And you're welcome!

Re: Linux 5.10 BTRFS performance regression

#90

Post by Quekid5 »

nicoburns wrote: post #31
jeromenerf wrote: post #20

Earlier quoted context omitted.

> Why does btrfs have those issues compared to other filesystems? Mostly because it has lots of features and as a consequence, is pretty large and complex. Closer to ZFS than ext2. Btrfs suffers from a initial bad rep, which is difficult to overcome.

ZFS itself seems very stable and not to suffer from these issues though.

ZFS is also extremely well designed at a system level... which is not the impression I get from BtrFS. (Disclaimer: I have not bothered looking at BtrFS for years because ZFS has handled everything I've thrown at it very admirably. Including complicated setups with RAID-Z, etc.)

Granted, there are some limitations to the design, but it doesn't affect my use cases, so whatever...

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