[vox-tech] Performance tuning for http file serving

[Bill Broadley]

On 04/14/2010 10:51 PM, Brian Lavender wrote:
> I would think that you need to tune your filesystem. How about this
> article on "On-demand readahead"
>
> http://lwn.net/Articles/235164/

Ah, I found this:
http://www.redhat.com/magazine/001nov04/features/vm/#tuning-vm

What I'd recommend is pick a design point.  Taking this graph:
http://broadley.org/bill/random-read.png

Then the number of clients you plan to have simultaneously, set 
min_readahead so you can have a reasonable memory footprint and good 
performance.

Say you only had a single few year old single 1TB disk (like in the 
graph).  If you set min_readahead to 2MB the I/O system should be able 
to provide 60MB/sec.

You should be able to manage 60MB/sec, the default on my disk was 128KB, 
which would lead to a bottleneck 12MB/sec or so.

Next time my mirror gets busy (likely around the LTS release) I'll see 
if I can collect some real world numbers.