Coordinating persistent status information with multiple file servers

Apparatus including

• a shared resource;
• a pair of servers each coupled to said shared resource and each disposed for managing at least part of said shared resource;
• a communication path disposed for coupling a sequence of messages between said pair, said communication path disposed for using said shared resource for coupling said sequence of messages;
• each one of said pair being disposed for takeover of at least part of said shared resource in response to said communication path;
• whereby said communication path prevents both of said pair from concurrently performing said takeover.

A method for operating a file server, said method including steps for

• controlling a subset of a set of shared storage devices;
• receiving and transmitting messages with a second file server, said steps for receiving and transmitting using a communication path including said shared storage devices;
• monitoring said communicating path and said shared storage devices;
• storing state information about said file server in a persistent memory;
• and
• performing a takeover operation of said shared resource in response to said steps for monitoring and a state of said persistent memory.

A method including steps for

• managing at a first server at least a part of a shared resource;
• receiving and transmitting a sequence of messages between said first server to a second server, using said shared resource;
• performing a takeover operation at a first server of at least part of said shared resource in response to said sequence of messages;
• whereby said steps for receiving and transmitting prevent both of said first server and said second server from concurrently performing said takeover operation.