Method and protocol for assuring synchronous access to critical facilitites in a multi-system cluster

A client process for maintaining a network resource, authorization to maintain the network resource being indicated by the contents of a lock data area stored on the network resource, the client process being configured to:

• send a first request to modify the lock data area to indicate that the client process is authorized to maintain the network resource;
• receive a first response indicating whether or not the client process has successfully modified the lock data area to indicate that the client process is authorized to maintain the network resource;
• and
• send maintenance commands to the network resource only if the first response indicates successful modification of the lock data area.

A lock server process for use in regulating maintenance activities performed on a network resource, comprising:

• a lock data area for indicating an ownership status of the network resource, the lock data area including lock owner data;
• and
• a lock server routine, the lock server routine being operative to receive an instruction to modify the lock owner data, the instruction including a set value and a test value, the lock server routine being operative to:
• compare the test value against the lock owner data;
• and
• replace the lock owner data with the set value if the test value is the same as the lock owner data.