load balance how to check server health

Hi,

I do have Cisco css load balance,  and three web servers (IIS7.5,  and many web site on there).

i want to setup Cisco to load balance my three web servers,   so i want to use cisco  keepalive uri  "/index.html",   then i can change index.html to notice cisco load balance which server active or suspend(  it's convenience  to deploy web site or do windows server update).

but have many web site on the server,   which folder i need store index.html   then cisco can detect it

many thanks

th