1. A multi-layer server system, comprising: a plurality of servers which are grouped into at least two layers of servers; load balancing means for monitoring work status of servers belonging to a first layer of the plurality of servers, for selecting one first layer server from the first layer servers based on first work status of the first layer servers which are monitored when the system receives at least one processing request from at least one processing request source, for connecting the process request source with the selected one first layer server, for facilitating selecting another first layer server among the first layer servers based on second work status of the first layer servers which are monitored after data requested by said one first layer server is made available by one second layer server belonging to a second layer of servers, and for connecting the process request source with the selected another first layer server; and shared memory means accessible by the information processors and for storing process information needed for starting the requested processing or resuming the requested processing after said one first layer server has stopped the processing therein, and a system controller for controlling the first layer servers and the load balancing means by instructing the selected another first layer server to resume the requested processing from said one first layer server thereby switching the processing among the first layer servers based on the second work status of the first layer servers.