Hi Dhilip,
When you start IIS LLAWP doesn't start automatically. LLAWP is only started when IIS receives an HTTP request. In Apache LLAWP starts whenever Apache is restarted.
In IIS Application pool there is a configuration which controls how often the application pool is recycled. In IIS6 by default application pool is recycled every 23 hours (not sure if this is same in IIS8). Also there is a setting to recycle application pool after processing certain number of requests also there is an idletimeout for Application pools. When the application pool is recycled then IIS will create new w3wp process.
Depending on how you have disabled the webagent. If you have modified the webagent ACO parameter EnableWebAgent to NO then Apache will still load the webagent module and LLAWP will be running. If you want to completely disable the webagent then in Apache conf file you should disable the 2 lines which loads the SiteMinder webagent library.
LLAWP process starts when Apache is started. In IIS it is started when IIS first recieves an HTTP request. But if the IIS process w3wp is shut down due to idletimeout then LLAWP will also shut down and will start again when IIS recceives an http request.
IIS is multi process multi threaded and so is Apache in worker mode.
Reason I said I am not sure whether all the parameter changes will take effect or not is because this is what CA documentation states:
Dynamic Host Configuration Object
With dynamic Host Configuration Object (HCO) updates, you can add Policy Servers to and remove them from a Policy Server cluster without needing to reboot the Web Server for the changes to take effect. The Web agent picks up the Policy Server changes dynamically and the Host Configuration Object is updated without a reboot.
It only talks about the Policy Server cluster. If you are not using clusters then you need to check withCA whether Dynamic HCO applies or not and whether all changes are applied or only policy server.
thanks,
Rajesh