FreeBSD MySQL still WAY slower than Linux

[Paul Mather]

On Tue, 2005-06-28 at 18:39 +0200, Roman Neuhauser wrote:
> # paul at gromit.dlib.vt.edu / 2005-06-28 11:38:44 -0400:
> > Note how the transfer rate for the "outside" is almost twice that of the
> > "inside."  Suppose I run tests on two different operating systems, one
> > of which resides in a partition on the "inside" portion and the other in
> > one on the "outside" portion.
> 
>     Which is not the case according to the OP...
> 
> > (Note that however good or bad it may be, the "location selection
> > strategy in the driver" can only lay out data within the confines of
> > the partition.)  Now, I do a "dd" test and find that the "outside" OS
> > is almost twice as fast as the other.  Would it be wise to conclude
> > that the slower OS is woefully inefficient compared to the faster one?
> > Suppose both tests turn out to take roughly the same time.  Should I
> > conclude that the OS residing on the "inside" is just as efficient as
> > the other OS?
> 
>     ... rendering this completely irrelevant.

...especially when you've cut out the context of my reply. :-)

My apologies if it wasn't clear, but I was responding to your apparent
assertion that location does not matter in disk performance benchmarks.
If I had been responding to a specific aspect of the OP's benchmark (or
indeed anything the OP has said), I'm sure I would have quoted that to
make the context clear.

>     I have seen people come to a freebsd list with completely flawed
>     comparisons or benchmarks: OSs installed on different partitions
>     side by side, not taking VM cache into account, whatever, and be
>     told that their numbers are flawed.
> 
>     I have also seen people test a specific subsystem (dd), and be told
>     that their numbers don't reflect real world.
> 
>     And I have seen people test real world performance (install FreeBSD,
>     install MySQL, run a stress test, reformat, install Linux, install
>     MySQL, run a stress test) and get responses that try to make up
>     reasons why the bad results are the testers fault). Heck, if
>     installing an operating system, a database, and running it isn't
>     a real world test, I don't know what is. Even if the bug is "FreeBSD
>     puts /var/db/mysql in the wrong part of the disk" (then it's still
>     a problem in FreeBSD, not in the messenger).
> 
>     I just wish people here were less defensive, that's all.

What you see as being defensive I see as being rigorous.  If someone is
making a claim based upon a performance benchmark, people will quiz the
person conducting the benchmark to ascertain exactly how it has been
undertaken.  To put any stock in a benchmark result, it is important to
be able to convince yourself it is a meaningful result.  Well, at least
most people I've encountered believe that to be the case.

As it says in the BUGS section of the diskinfo man page: "There are in
order of increasing severity: lies, damn lies, statistics, and computer
benchmarks." ;-)

Cheers,

Paul.
-- 
e-mail: paul at gromit.dlib.vt.edu

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