Dual node problem

Question

Problem:
I have a Sun box with 2 nodes (2 CPU's with non-shared memory but shared hard disk).
A Java developed system will be running concurrently on both nodes (i.e. failure reduction).
The problem is that both processes need access to a common registry (with fast access, several million accesses per day). Therefore the registry will be in the memory of one of the nodes, but what happens if that node fails then the other node won't be able to access the registry. Since this defeats the object of 2 nodes I need a solution.
Any ideas?? I'm stumped short of introducing a third node!!
Thanks in advance
Nick

Answer 1

Does your several million accesses per day negate the option of using a file on the shared disc - to contain the common registry
You could use another file as a semaphore to control which Node has got access rights (BUT you would have to build in some sort of Semaphore release timeout in case of NODE failure) - do the nodes share a common clock source for file write timestamping ??
Otherwise, I guess you wil have to build in some sort of Registry replication and 'handshake' mechanism to determine loss of the other Node - perhaps by having the 2 Nodes exchange a counter of elapsed time since Node start-up (ie the longest running Node should have the latest Registry settings)