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Linux 5.10 BTRFS performance regression

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Re: Linux 5.10 BTRFS performance regression

#71

Post by gregkh »

est31 wrote: post #63
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…

On the bright side updating to 5.10 fixed a regression of a 5.4 to 5.8 kernel upgrade to me. The fix might have been in 5.9 but I only got the idea of upgrading after the 5.10 release. Anyways, Linux needs some more CI so that such bugs can be found during the RC phase.

Where in the current CI that we have today is lacking that needs to be improved? We always want more testing and testers, what is preventing everyone from helping with this?

Re: Linux 5.10 BTRFS performance regression

#72

Post by NavinF »

solarkraft wrote: post #48
m1gu3l wrote: post #5

The ratio of bad to good posts about BTRFS always made me wonder why anyone would roll with it. Don’t put your fs in crazy.

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.

Re: Linux 5.10 BTRFS performance regression

#73

Post by bitL »

turminal wrote: post #4
kzrdude wrote: post #2

Assuming it can be fixed in a 5.10.x patch release, it's a rather minor story - a bug that is quickly found after release and fixed, hopefully. It will be investigated: https://marc.info/?l=linux-btrfs&m=160869337604422&w=2

The problem with btrfs is that it has quirks like that (and worse, much worse) all the time.

I'd prefer performance regressions any day compared to losing my data because BTRFS had a bad day like was common in the past. I also no longer use BTRFS, once was enough. If a performance regression leads to ZFS-like stability, bring it on!

Re: Linux 5.10 BTRFS performance regression

#74

Post by tremon »

dmm wrote: post #54
redis_mlc wrote: post #15

I wish to god people would get a clue with BTRFS: - don't use it because you think the name is "cool". Every time I go to a linux meetup, some idiot starts talking about the name. - it takes 5-10 years for a filesystem or database to mature after it's released. Otherwise you will lose data and cry. - the recent BTRFS performance improvements are against itself, not other filesystems. EXT4 is an excellent fs, as good…

> - it takes 5-10 years for a filesystem or database to mature after it's released. Great news! BTRFS was introduced in the mainline kernel in March 2009! It's been ten years.

And it's been the default filesystem for openSUSE (system partitions only) since December 2015 [0], so there's been plenty of real-world usage too.

[0] https://en.opensuse.org/Portal:13.2

Re: Linux 5.10 BTRFS performance regression

#75

Post by ksec »

xaduha wrote: post #59

You can get 'surplus' HP P410 from Ali or Ebay, they are cheap and work just fine. Always was told that you can't beat hardware RAID and now that they are available people don't seem to be interested. Just looking at it I can say that apart from CPU/GPU chips themselves it's the best piece of electronics in my PC.

>Always was told that you can't beat hardware RAID

Is that new?

I have always been told to avoid hardware raid when possible.

Re: Linux 5.10 BTRFS performance regression

#76

Post by xaduha »

BuildTheRobots wrote: post #70
xaduha wrote: post #59

You can get 'surplus' HP P410 from Ali or Ebay, they are cheap and work just fine. Always was told that you can't beat hardware RAID and now that they are available people don't seem to be interested. Just looking at it I can say that apart from CPU/GPU chips themselves it's the best piece of electronics in my PC.

Where as I was always told to avoid hardware raid if possible, and that's been a mantra for 15+ years. The reason I was given is twofold. 1) If your RAID card dies it's nice to be able to plug drives into any controller and be able to access the data. 2) "look at how often MDADM fix bugs. Now look at how often your RAID card firmware gets fixed... use MDADM". Modern filesystems like btrfs & zfs both prefer to deal wi…

> Now look at how often your RAID card firmware gets fixed

It was updated plenty, from 1.58(B) (earliest I can find) to 6.64(B)

https://support.hpe.com/hpsc/swd/public/detail?swItemId=MTX-...

I'm not recommending some abstract hardware RAID, I'm recommending this particular card for personal use, with backup obviously. Although if you just use RAID 0 or 1, then data is perfectly readable outside of RAID with a normal SATA controller.

Re: Linux 5.10 BTRFS performance regression

#77

Post by xaduha »

ksec wrote: post #75
xaduha wrote: post #59

You can get 'surplus' HP P410 from Ali or Ebay, they are cheap and work just fine. Always was told that you can't beat hardware RAID and now that they are available people don't seem to be interested. Just looking at it I can say that apart from CPU/GPU chips themselves it's the best piece of electronics in my PC.

>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.

Re: Linux 5.10 BTRFS performance regression

#78

Post by ksec »

bluedino wrote: post #50
m1gu3l wrote: post #5

The ratio of bad to good posts about BTRFS always made me wonder why anyone would roll with it. Don’t put your fs in crazy.

Synology has been using BTRFS for a while, I haven't had any issues with it. https://www.synology.com/en-global/dsm/Btrfs

Unfortunately not available on every model.

Re: Linux 5.10 BTRFS performance regression

#79

Post by yjftsjthsd-h »

throwii wrote: post #43
tobias3 wrote: post #35

Earlier quoted context omitted.

My guess is this (compared to ZFS): With a CoW-file system like btrfs you have to problem that you need new file system space to delete something. This is problematic if the file system is full and you want to be able to write to it again by deleting something. ZFS solved this by just saying one can only fill a file system to 90% usage. At some point they even decreased this (during upgrade) and I had the issue that…

Interesting decision they made, I wonder whether they would decide differently now after seeing all the complexity. So Rust does not decrease the complexity, but only removes certain kinds of errors which the compiler can detect. Neither logic errors nor speed regressions. Thank you for your input.

> I wonder whether they would decide differently now after seeing all the complexity.

Decide what? Cow is a fundamental part of how btrfs works, and Rust didn't exist for the majority of Linux's life. (Although if you're into that, look at Redox)

Re: Linux 5.10 BTRFS performance regression

#80

Post by kefyras »

zaarn wrote: post #46
flemhans wrote: post #16

Earlier quoted context omitted.

Is ZFS not ready for use? I was going to use it in production next year.

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.

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