Explanation/Reference:
Explanation:
A: How does the disk heartbeat work?
Every node writes every two secs to its block in the heartbeat system file. The block offset is equal to its global node number. So node 0 writes to the first block, node 1 to the second, etc. All the nodes also read the heartbeat sysfile every two secs. As long as the timestamp is changing, that node is deemed alive.