Eddie contains in-built real-time load monitoring
routines to track the usage of each Back End Server (shown in black) on
your site. This information is passed to a set of designated Front End
Servers (shown in blue) which perform load balancing of incoming transactions
across all servers supporting particular applications.
The Front End Servers take the load information and adjust the fraction
of new client requests sent to each Back End Server so as to ensure
that all servers are operating below designated target thresholds (for
example, maximum CPU load).
The Front End Servers do not need to know
anything about the make, model, or processor speed of the servers at
the site. There is no requirement that the servers at your web site are
configured the same way. There is no requirement that servers at a site
have the same capacity. In fact, there is no requirement that they even
run the same operating system!
The capacity of each Back End Server is
automatically learned in real-time and adjusts as the mix of client
requests changes. Therefore, changes in client request patterns are
detected and admission control and balancing adjusted accordingly,
without manual intervention. Furthermore, servers are upgraded,
absolutely no reconfiguration of Eddie is required.
For server sites
distributed over a city, a country, or even the world, Eddie's Enhanced
DNS allows the entire site capacity to be usable. The
individual sites may have different numbers of servers, different
vintages of computer, even different operating systems.
information passed to each Front End Server within a site is processed
and then summary information of the Front End and Back End Servers on
each site is passed to each of Eddie DNS server. The Eddie Enhanced
Domain Name Service (DNS) software then dynamically balances
client domain name resolution requests across all sites in the
distributed server-site, and more specifically, across each Front End
within each site. This ensures maximum efficiency of server resources
within the distributed site.