[Tilecache] Number of simultaneous hit for tilecache (on apache with mod_python)

[Guillaume Sueur]

As Chris said, 1300 req/sec is already a pretty good performance.
Basically I don't think increasing the CPU load can help you going
further. As the tiles seem to be already generated, there is no CPU
usage for generating them, and your CPU load is just roughly Apache load.
The best performances I've had were with a complete cache and Lighttpd
serving the tiles with an OpenLayers Tilecache layer (which hits
directly the images as Chris said). Lighttpd is very efficient on static
files, with a lesser memory fingerprint than Apache. You can even handle
its 404 and have it pointed to tilecache if your cache is not complete.
For heavy loads, you can also add a Squid reverse proxy on another
server, which will store the most used tiles on its own file system.


Regards,

Guillaume


Martin Ouellet a écrit :
> Hi,
> 
> I've made a cache of 30k tiles on disk (200Mo).  The network team that I
> work with want to test tilecache to see how he will behave if our Web
> site receive a huge amount of user simultaneously.  So I send them a
> list of URL with ramdom BBOX so they can call tilecache in a loop to
> test it.
> 
> They simulate 8 users at the same time and the result is pretty good
> actually (about 1300 tile /sec.).  but to obtain this result, the CPU is
> only running at 27% of his capacity and even if they increase the number
> of user, this percentage remain almost the same.  So we were wondering
> how we could use more efficiently the CPU and at the same time, increase
> even more the performance of the tile serving
> 
> Does someone have an explication for this situation?
> Can we suspect an apache, python or mod_python, windows limitation?
> 
> Here's the technical spec of my server
> 
> OS
> 
> 	
> 
> Windows Server 2003 SP1
> 
> CPU
> 
> 	
> 
> 8 cores* Intel XEON X5450 @ 3,00 Ghz
> 
> Memory
> 
> 	
> 
> 3,25 Go
> 
> 
> thank you in advance!
> 
> MartinO
> 
> 
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