[Btrfs-devel] On FS benchmarks

[Chris Samuel]

On Fri, 4 Jan 2008, Yannick Gingras wrote:

> Greetings,

Hi Yannick,

> Zach Brown pointed me to Btrfs after I published my own flawed
> attempt to benchmark the too many files problem on GNU/Linux.

This one ?

http://ygingras.net/b/2007/12/too-many-files:-reiser-fs-vs-hashed-paths

> Bonnie++ is a popular tool to benchmark FS performances but it's
> hard to extend.  As an example, I wanted to measure the impact of
> path hashing and I would have had a hard time doing that with
> bonnie++.

You could always approach Russell Coker about making it easier to 
extend as he's still working on what will be v2.0 of Bonnie++.  He's 
a nice guy and quite approachable (and is a fellow Aussie, always a 
bonus :-)).

http://etbe.coker.com.au/2007/12/03/new-bonnie-releases/

> Is there a need for a unified benchmarking system with easy to
> write plugins?  I think so.  Over time, more plugins would be added
> and the overall measurement would become less (more?) flawed.

I reckon it's a good plan, and Joe Landman over at Scalable 
Informatics has one, though his "Bioinformatics Benchmark System" is 
not aimed at directly testing disk I/O but rather at benchmarking 
applications.  Still, it is GPL'd and so if i is truly pluggable then 
you might be able to take advantage of it..

> But I digress.  On your benchmark page [1], most tests have
> detailed methodology.  Aside from those, what benchmark tools do
> you use to compare the performance of Btrfs with that of other file
> systems?

When I commissioned to write an article for LinuxWorld on "Emerging 
Linux Filesystems" [1] (including btrfs, NILFS, Reiser4, etc) earlier 
in the year I decided I'd take a mix of both real world tasks and 
synthetic benchmarks and try and mix them up.   Seemed to work 
reasonably well and produced a few surprises for me!

Certainly coming from the HPC clustering world the answer you would 
get to that question there is that the best benchmarking load to test 
(the only one that really matters in the end) is your *own* workload.

The problem then is simulating it.. ;-)

[1] - http://www.csamuel.org/2007/12/11/emerging-linux-filesystems

-- 
 Chris Samuel  :  http://www.csamuel.org/  :  Melbourne, VIC

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