Example: odd-nodes cluster
+-------------------------------------------+
| site3 |
| |
| +-------------+ +-------------+ |
| | | | | |
| | arbitrator1 | | arbitrator2 | |
| | | | | |
| +-------------+ +-------------+ |
| |
+-------------------------------------------+
+-------------------------------------------+ +------------------------------+
| site1 | | site2 |
| | | |
| +--------------------------------------|-----|-----------------------+ |
| | cluster | | | |
| | | | | |
| | +-----------+ +-----------+ | | +-----------+ | |
| | | | | | | | | | | |
| | | node1 | | node2 | | | | node3 | | |
| | | | | | | | | | | |
| | +-----------+ +-----------+ | | +-----------+ | |
| | | | | |
| +--------------------------------------|-----|-----------------------+ |
| | | |
+-------------------------------------------+ +------------------------------+
- Total: 5 votes
- Majority: 3 votes
Site1 Isolated
node1 standpoint:
- live nodes: 2 (node1, node2)
- arbitrators votes: 0
- votes: 2
=> node does not have quorum, commits suicide
node2 standpoint
- live nodes: 2 (node1, node2)
- arbitrators votes: 0
- votes: 2
=> node does not have quorum, commits suicide
node3 standpoint
- live nodes: 1 (node3)
- arbitrators votes: 2
- votes: 3
=> node has quorum, does not commit suicide
Site2 Isolated
node1 standpoint
- live nodes: 2 (node1, node2)
- arbitrators votes: 2
- votes: 4
=> node has quorum, does not commit suicide
node2 standpoint
- live nodes: 2 (node1, node2)
- arbitrators votes: 2
- votes: 4
=> node has quorum, does not commit suicide
node3 standpoint
- live nodes: 1 (node3)
- arbitrators votes: 0
- votes: 1
=> node does not have quorum, commits suicide
Node2 Dies
node1 standpoint
- live nodes: 2 (node1, node3)
- arbitrators votes: 2
- votes: 4
=> node has quorum, does not commit suicide
node3 standpoint
- live nodes: 2 (node1, node3)
- arbitrators votes: 2
- votes: 4
=> node has quorum, does not commit suicide
Node2 and Node3 Die
node1 standpoint
- live nodes: 1 (node1)
- arbitrators votes: 2
- votes: 3
=> node has quorum, does not commit suicide