1. A system for use in achieving distributed data storage over a computer network comprising: a storage server system comprising one or more storage servers that each comprise a data storage device and a network interface for communicating with an application client that will require data storage and a management storage server; and a management storage server system comprising one or more management storage servers that each comprise a network interface for communicating with an application client that will require data storage and each of said one or more storage servers; wherein each of said management storage servers comprises a data storage configuration identifier whose value is indicative of an allocation of data storage within said storage server system at a point in time; wherein an allocation of data storage within said storage server system comprises defining one or more virtual volumes of data storage distributed over one or more of said storage servers; wherein each of said management storage servers is capable of providing a first value for said data storage configuration identifier to an application client; wherein each of said management storage servers is capable of providing a second value for said data storage configuration identifier to each of said storage servers after there is a change in the allocation of data storage within said storage server system; wherein each of said storage servers comprises a comparator capable of: (a) comparing said first value for said data storage configuration identifier which is associated with a data storage related request received from an application client with said second value for said data storage configuration, and (b) ignoring said data storage related request if said first value is not equal to said second value.