fenio

Thanks, all three are fair points.

1. XFS reflink is enabled and its reflink/CoW-break measurements do run. The dashboard button currently means “native/full-CoW filesystem family”, not “supports reflink”, but that distinction is not clear from the label. I’ll rename it to “Native CoW” and add a separate reflink-capable filter that includes XFS.

2. The current integrity comparison is XFS on LVM/dm-raid10 with dm-integrity in its default journal mode. It is not mdraid and not bitmap mode, so your suggested stack would be a genuinely different and useful data point. An md RAID5/6 over per-member bitmap-mode dm-integrity comparison against RAID-Z1/Z2 makes sense, with the weaker post-crash bitmap semantics documented.

3. I did not pin or record the scheduler, which is a reproducibility gap. The dedicated SAS machine currently has mq-deadline active on all HDDs and SSDs. I’ll add queue/scheduler metadata to results before considering separate scheduler variants, since it can strongly affect the mixed and latency-sensitive phases.

First hybrid tier run: https://bartosz.fenski.pl/modern-fs-benchmark/sas-hdd/hybrid... It is FIRST run... I will probably start tuning it now. And I'm open for suggestions what and how to tune ;)

Should be fixed. Thanks.

It's not easy to show so many data and make everyone happy about the way it is presented. In fact I'm aiming more at engineers and trying to provide as much info as it is possible to be clear about methodology and everything around it. But raw data is in JSON files so you can always make PR for creating additional view aimed at philosophers and not engineers ;)

The new machine - I mentioned in the other thread - has both HDDs and SSDs so tests with mixed topologies are planed.

I extended info about setup. Should be visible in top part of benchmark.

I answered in other thread how exactly integrity check looks like and why the name might be misleading. I'm also in the middle of updating descriptions to be more adequate. Thanks for pointing that out.

Speaking about standard industry metrics.

fio is an established tool, and throughput, IOPS, fsync latency, and percentiles are standard concepts. However, the exact job recipes and the composite “Overall Core” score are project-specific.

The trivial-operation test is also custom: one 4 KiB write plus fsync every 200 ms. The idle window contains at most about 50 operations, so its p99 is effectively the slowest sample’s fio histogram bucket, not a statistically stable population percentile. It should be treated as a small-write durability-latency probe, not a universal application metric.

But after all all tests are in the repository. If they need tweaks, changes I'm open to do so... I started from scratch and did whatever came to my mind. Some tests are added after my initial link here which went mostly unnoticed several weeks ago but I got some requests for more tests which I implemented.

But to sum up. I want this test to be useful so feel free to open PRs with improvements. It's not like I've got some agenda. In fact I wrote here and there on the page that I'm counting on communities of various filesystems to provide improvements, changes etc to make their filesystem shining.

This is personal project made when I realized that multiple-devices benchmarks were almost completely absent. Since I had not access to real hardware I decided to make at least initially everything based on GH runner with all the limitations that came with this approach. I tried to limit these limitations as far as I could. But feel free to submit bugreports, PRs, propositions for improvements.

The current “Integrity” label is broader than the test actually proves, and I’m changing it to “Corruption probe.” FAIL means that file changed or became unreadable. SURVIVED means only that the file remained readable and hash-identical. It does not prove the entire filesystem was healthy, that every overwritten byte was allocated, or that all 2 GiB were repaired.

Thanks for pointing it.

For the main linked benchmark there are no dedicated test hypervisors. It's all based on GH runners with all the limitations and quirks that came with it.

Real hardware is used in: https://bartosz.fenski.pl/modern-fs-benchmark/real-hw/ https://bartosz.fenski.pl/modern-fs-benchmark/sas-hdd/

But unfortunatelly it's much more limited number of actual runs. sas-hdd is still in progress so numbers for it should increase over time.

Obviously they could and probably were noisy neighbours. I'm not trying to hide that fact. Initial step for every benchmark is test of underlying device to at least reject completely unlucky cases. Also after almost 600 runs average is probably more or less correct...

Also take a look at tests on real hardware. There are not many of them but there are some. I pointed to them in my first answer.

what exactly would you like to improve?

The author of the benchmark here. I went over some comments and I'll try to tackle them here. I'm pretty clear that GH runner based benchmark is far from perfect due to noisy neighbours etc. Thus every test first is running so called calibration... to reject completely unreliable VMs. I'm fully aware that this can't completely fix the issue. Can limit it but not fix. But as of now there are 593 runs recorded so average should still be quite meaningful.

Having that said I'm desperately trying to get REAL hardware to run that benchmark. With some successes ;)

Few months ago I got Hetzner machine from Kent Overstreet and I was able to finish 3 runs before machine died... Results: https://bartosz.fenski.pl/modern-fs-benchmark/real-hw/

Currently I've got even more interesting machine with tons of disks and I'm running new set of benchmarks but it's really in its initial stage.

https://bartosz.fenski.pl/modern-fs-benchmark/sas-hdd/ 2nd run in progress... one run on REAL hardware takes much more time than on GH runner so it's slow.

But this new hardware has also so many disks that the plan is to try also more complex, tiered cache topologies. I'm working on it.

I'm happy to answer any other questions, sources of every piece of this benchmark are freely available and I'm not saying they are 100% correct. I'm open to improvements.

I'm working on my own NAS system based on NixOS and bcachefs. https://github.com/nasty-project/nasty