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Posted by farlight 4 hours ago

Btrfs/ZFS/bcachefs under workloads classic benchmarks skip(bartosz.fenski.pl)
70 points | 67 commentspage 2
farlight 4 hours ago|
https://github.com/fenio/modern-fs-benchmark
markhahn 2 hours ago||
what does "integrity" fail mean in the first table? that the case didn't recover from the 2G corruption?
fenio 1 hour ago|
[flagged]
blop 3 hours ago||
For peace of mind I'm still using zfs (since the last 15+ years) but I'm definitely not impressed by the performance...
throwaway270925 16 minutes ago||
Depending on your current setup, dRaid can give you quite the performance boost nowadays, since its data slabs are spread out over all disks in the array its using all of the disks bandwith combined.
slyfox125 3 hours ago|||
Different tools for different jobs; use ZFS for your data store and ext4 for your primary drive.
blop 3 hours ago||
yes indeed, zfs for my nas basically
badgersnake 1 hour ago||
zfs-mirror-8k (whatever that is) looks alright.
blop 3 hours ago||
I think the reviews should also include the social aspect of these filesystems...

There is and have been many promising and exciting FS to replace the old boring ones, but for storage you not only want to avoid technical issues but also maintainer(s) drama...

koverstreet 2 hours ago||
Why do people keep bringing up drama?

The community infighting has sucked, but that's a thing that matters primarily for maintainers.

I think most users just want something that works.

blop 14 minutes ago|||
drama matters because most users don't want to have their favourite FS randomly removed from the kernel unexpectedly after some OS update :)

That said I certainly hope that one day the technical advantage of bcachefs will be so overwhelming that maybe the decision to remove it will be overturned. And if big vendors make it their default FS the bus factor will disappear (even if unofficially you'd still be the sole maintainer, but no one cares about that in the enterprise world...)

Skunkleton 2 hours ago||||
Related username?

To answer the original question, most people who care about their filesystem at all care about its stability. Not just "does it work now" but also "will it work and improve over time". Infighting puts the future at risk.

koverstreet 2 hours ago||
It really does.

But you might want to check out the bus factor on btrfs too; when a maintainer says "but we've saved Facebook billions and billions of dollars!", calls for the other filesystem maintainer to be ejected from the community, then quits to join Anthropic a month later - that's not a vote of confidence.

I'd be very happy if people could just stop bringing up drama and us factors. We put it behind us a year ago, but it seems not everyone got the memo.

throwaway85825 1 hour ago|||
I don't care about the drama, I just want to say thank you for your continued work to advance the state of the art in open file systems.
koverstreet 1 hour ago||
Appreciate it :)
badgersnake 1 hour ago||
Reiserfs was the OG drama fs
blop 1 hour ago||
That's what I meant, it's always risky to rely on a single person for such an important subsystem as storage... I'm also very sad that bcachefs has been kicked out of the kernel, it is really a very promising FS.

So that leaves btrfs which always seemed complex and brittle to me (compared to zfs at least)

azatom 1 hour ago||
clicked, ctrl+f ssd, hdd, not found, closed
azatom 55 minutes ago|
In filesystem subject a proper critique is mentioning ssd vs hdd. I did not added value for karma increase, but karma lost? Who haven't I wished a happy birthday?
Farmadupe 3 hours ago|
@farlight assuming that you're the creator do you think you'd be able to rework the HTML/CSS? I'm sure you've got good data but speaking on behalf of my eyeballs, the results page is... hard to read!
Farmadupe 3 hours ago||
> 2G of random garbage is written directly onto one member device (behind the filesystem's back, offset 1G — python injector; uutils dd mis-seeks on dm devices), caches dropped, then a full scrub: btrfs scrub -B, zpool scrub + wait, bcachefs scrub, md/lvm sync-action 'check' (which can only COUNT mismatches — no checksums to know which copy is right).

I'm not sure that nuking 2G of the underlying block device is a recoverable error on any filesystem that I'm aware of? Can you confirm if any ofthe filesystems really came out of the other side in a usable state after scrubbing?

-----

> Trivial-op p99, idle (ms) # A trivial operation — one 4k write + fsync every 200ms (like a shell appending history or an editor updating its swap file) — run alone for 10s. p99 of the fsync completion

In fact, if it's OK for me to ask, are any of the metrics tht you used standard industry metrics? It looks like several of the tests are bypassing the kernel's page cache? -- which I worry may fall into the trap of "I modified the system to be unrepresentative of reality and then tested it".

----

> kernel 7.0.0-1012-azure

Can you confirm if you tested on a bare metal machine? were you the only tenant?

matja 1 hour ago|||
> I'm not sure that nuking 2G of the underlying block device is a recoverable error on any filesystem that I'm aware of?

ZFS and btrfs were designed from the start to handle this, by using checksums on every piece of (meta)data and redundancy to return the same data as was stored to the kernel, and rewrite the bad data.

I've tested my own machines running ZFS by random writes out of band from the filesystem/kernel and it has always found and fixed them.

vlovich123 3 hours ago||||
1 device out of the replica set I’m assuming so all of them should recover.
hlieberman 3 hours ago|||
The integrity check is only on the tests which are either RAID or the filesystem equivalent.
fenio 2 hours ago||
what exactly would you like to improve?
Farmadupe 1 hour ago||
I'd actually recommend some excellent books on the "philosophy" of data presentation: The first that comes to mind is "the visual display of quantitative information" by Edward Tufte seems to be freely available online, and the other one on my mind is "how charts lie" by Alberto Cairo (which doesn't seem to be freely accessible)

But if it helps, just some "initial gut feel observations" from me:

* It's definitely not possible to find issue with the the _sheer amount_ of results, but there's just far too much for a human to absorb, all presented at once

* Overall text size is quite small, and difficult to read

* The page doesn't make a strong statement of _what_ is under test: the first words are: "modern-fs-benchmark Multi-device CoW filesystems under workloads classic benchmarks skip" -- which defines the webpage in terms of what it is _not_, without stating what benchmarks are actually present.

* The first line of teh page contains run statistics that probably eithre want to b at the bottom, or just don't need to be in the webpage at all: "latest run 2026-09-18 18:50:45 UTC, kernel 7.0.0-1012-azure, 593 runs recorded · 145 trend points shown"

* A significant proportion of the free text is caveats. There's nothing wrong with being transparent about limitations, but they may be a sign that there might be alternative ways to present the data, or that the data may be flawed (depending on the caveat)

* Theres several categories that I think have been invented for the purpose of collation, but I don't think are defined on the page. I think "Overall Core" and "Core I/O" aren't explained, which means by definition it's impossible for a reader to understand the score table.

* And as we're all aware right now, current Claude models are currently struggling to write coherent English. There's several incoherent sentences on the page. It's a Claude issue.

koverstreet 1 hour ago||
Speaking as someone who consumes this, I appreciate how it's laid out. As a developer, we can often see at a glance where the bottleneck is if we have enough data laid out - IOW, data overload for you is me feeling like a kid in a candy store.

Sometimes there are ways to make things easier without dumbing them down, but way too many people conflate the two; I get nervous when non engineers say "I've studied this, it should be easy".

Farmadupe 1 hour ago||
ah, yes that's obviously fine; I'm definitely coming fromt he perspective of "bored guy on a Saturday evening who happened to stumble across someone else's wall of charts on HN"
koverstreet 1 hour ago||
I think the Phoronix test suite does pretty well for the end user who wants something easy to digest; the exact choice of benchmarks is sometimes odd but the harness itself is quite good.

At some point I'd like to get our own automated pts runs going, since Michael is not consistent with what hardware he tests on and he hasn't been consistent with getting them out.