FreeBSD IO Performance (was Re: Quality of FreeBSD)

[Chris]

Its been mentioned before and most experience the same as you by
setting it to 16 a dramatic improvement in the sequential read, I
currently run all my 5.x servers like this with no issues as a result.
 I am curious if the default will ever be changed.

Chris

On 22/07/05, Mark Kirkwood <markir at paradise.net.nz> wrote:
> I happened to have received a 'new' machine, and wanted to see what its
> IO system was capable of. So took the opportunity to run 4.10 and 5.4
> against each other a few times. (fresh re-installs each time).
> 
> Its documented at:
> 
> http://homepages.paradise.net.nz/markir/freebsd/
> 
> I wanted to play with Docbook as well :-), so excuse the "book" format
> (might be a few typos too).
> 
> But to cut to the chase, the results were overall very similar - 4.10
> probably a little (4-8%) faster (allowing for run variation). So really
>  5.4 is reasonably fast. The actual figures weren't too bad either -
> 70-80Mb/s read and writes on a 2 disk ATA array.
> 
> The most interesting thing discovered, was 5.4's "out of the box"
> sequential *read* performance was considerably less then 4.10, but could
> be brought up to almost the same by setting.
> 
> vfs.read_max=16
> 
> Hope this provides some interest, again - gotta qualify, this is all one
> man's experiment on his hardware...
> 
> Cheers
> 
> Mark
> 
> P.s : of course, it would be nice if 5.x (or perhaps more importantly
> 6.x) was *faster* than 4.10....
> 
> Michael Schuh wrote:
> > Hi,
> >
> > Now my question to you : is the performance of ata-related disk-access
> > under UFS-Filesystem not important for other application, so that the
> > performance can be a half of them that RELENG_4 does?
> >
> > In fact under RELENG_4 i can write a GIG FIle double as fast as under
> > RELENG_5 ! and i would not hear any thing about serial performance or
> > that this is not really like the real world, if i syimulate that with:
> >
> > /usr/bin/time dd if=/dev/zero of=/zerofile bs=1024 count=1024k;
> > this is reality poor!
> >
> 
> 
> 
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