Patent ID: 8296533

Claim:
A virtual server system comprising: an administrative server; a plurality of servers, each being configured to be managed by the administrative server and to have a server virtualization facility and a virtual server; and a plurality of virtual disks, each of which is allocated to a respective one of the virtual servers, wherein the server virtualization facilities and the administrative server are configured such that, if a condition of the virtual server in one of the plurality of servers has been changed, in the virtual server system, the server virtualization facility deletes information stored on the virtual disk allocated to the virtual server whose condition has been changed, and the administrative server stores a load condition of the server and, based on a result of the storing, selects one of the servers for deletion, the selected server being that which has the server virtualization facility deleting the information stored on the virtual disk, wherein in each of the plurality of servers, the server virtualization facility is further configured to divide a capacity of the virtual disk into several blocks and erase information stored in the virtual disk for each divided block.