Fault tolerant NFS server system and mirroring protocol

A server computer system providing for the fault-tolerant serving of data mutually communicating over a network with another server computer system and a client system in response to a network request having a source address and a destination address, said server computer system comprising:

• a) a mass storage device;
• and
• b) a processor coupleable to a communications network, said processor being coupled to said mass storage device and providing for the exchange of data between said communications network and said mass storage device in response to a predetermined request for the transfer of data by a client system, said processor including
• means for defining qualifications applicable to the transfer of predetermined data;
• and
• means, capable of distinguishing between a multiplicity of destination addresses, for processing network requests having one of a plurality of destination addresses, said processing means selecting between a plurality of response processes based on the destination address of said predetermined request, at least one of said response processes providing for the confirmation of the mutual performance of said predetermined request with another server computer system.

A fileserver system comprising:

• a) a first server system including a first mass storage device providing a first data storage area;
• and
• b) a second server system including a second mass storage device and providing a second data storage area,
• said first and second server systems being separately coupleable to a network that provides for the transmission of network requests between a client system and said first and second server systems, said first and second server systems each including means for selectively processing network requests having a predetermined network destination address, said first and second server systems each including means for coordinating between said first and second server systems the loosely concurrent processing of network requests having said predetermined network destination address by said first and second server systems.

A process of cooperatively operating a plurality of file server computer systems with respect to a client computer system coupled to said plurality of file server computer systems by a communications network, said process comprising the steps of:

• a) transmitting by said client computer system a predetermined file request onto said communications network;
• b) selectively receiving said file request by a first file server computer system, said first file server determining to perform said predetermined file request, selectively performing said predetermined file request and transmitting a predetermined file request response onto said communications network to said client computer system;
• and
• c) selectively receiving said predetermined file request by a second file server, said second file server determining to perform said predetermined file request and selectively performing said predetermined file request.

A method of operating a file server having a processor, a data storage device, and a network interface coupleable to a network for transmitting and receiving network messages including file requests and file responses, said method comprising the steps of:

• a) establishing a first network address for enabling receipt of network communications;
• b) establishing a proxy network address for enabling receipt of file requests by said network interface, said proxy network address being shared with another file server;
• c) receiving a predetermined file request identified by said proxy network address, said predetermined file request defining an operation to transfer file data with respect to said data storage device;
• d) determining whether to perform a file operation against said data storage device, responsive to said predetermined file request, as a primary or secondary file server with respect to said proxy network address;
• e) performing said file operation either as a primary or secondary file server including, when performing said file operation as said primary file server, transmitting a file response with said proxy network address and responsive to said predetermined file request to said network and, when performing said file operation as said secondary file server, selectively transmitting an acknowledgement message to said another file server.