System Configuration

[Milo van der Linden]

Another option I am currently investigating for the static components of 
my maps is tilecache (google it). That should at least take away some of 
the load that mapserver rendering the image in memory will eat up.

Another option is to combine mapserver with fastcgi. There should be 
documentation around.

Good luck, and indeed as Frank suggests, consider hiring an expert. 
Frank will know one or more ;-)

Frank Warmerdam schreef:
> Bruce Cheney wrote:
>> We have been given a requirement to support 5000 simultaneous 
>> users.   What we are finding is that MapServer bogs down around 400 
>> simultaneous users on a test machine.  It looks like it is likely 
>> slowing because of the threading issue.  We haven't tested on a 
>> production machine but are estimating that it should support double 
>> what are test machine could handle (double the processor and RAM).  
>> So at least 800 simultaneous users.  Divide that out with the 5000 
>> and we need a minimum of 6-7 web servers supporting MapServer.  We 
>> will certainly scale this as is needed but I do need some idea going 
>> in as to what is going to be required.
>
> Bruce,
>
> I'm curious how many map requests per minute you expect 800 simultaneous
> users to generate.
>
>> Does this sound like results that others expect or is this quantity 
>> above what others have tested?  Also Does anyone know of a solution 
>> in the works to run make mapserver thread safe and/or up the overall 
>> speed?  I am not complaining about the speed just wondering what is 
>> in the works.
>
> In various aspects MapServer is already thread safe though there are
> also known "unsafe" components, and some components are wrapped by
> big locks that significantly reduce the value of multiple threads.
> Progress occurs by fits and starts, largely based on support from user
> organizations depending on multi-threading.  For instance, in 5.0 I
> implement locking around OGR for a client of mine in Australia.
>
> (This is a subtle way of suggesting you hire someone to make this
> happen if it is what you want!)
>
> All this aside, by default MapServer is *massively multi-threaded*.
> I say this since the default operation is to start a new cgi instance
> for each request - each is essentially an independent thread.
>
> Of course, the downside of whole-process cgi style multithreading is
> that very little context is preserved from request to request.  Map
> files, data file headers, etc all need to be reparsed for each request.
> My point here is that you need to think carefully about the application
> flow to take much advantage of multiple threading within a single 
> process.
>
> Also, if I may channel Ed, if you wanted to squeeze more performance out
> of mapserver, you really need to start by figuring out what it is 
> spending
> it's time doing.  Where is it spending it's time?
>  o waiting for disk?  (perhaps you are reading more data than you need?)
>  o rendering (perhaps your data is overdense, or you are using expensive
>    rendering options?)
>  o parsing mapfiles (perhaps you mapfile has too many unused layers?)
> etc.
>
> Best regards,


-- 


	

Milo van der Linden
skype: milovanderlinden <skype:milovanderlinden?add>
mlinden at zeelandnet.nl <mailto:mlinden at zeelandnet.nl>
milovanderlinden at gmail.com <mailto:milovanderlinden at gmail.com>
milo at 3dsite.nl <mailto:milo at 3dsite.nl>
http://www.3dsite.nl

	  	

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