Although private cluster container partitions protect against two nodes being active on the same partition, there are circumstances where the protection they offer is insufficient. For example, if each of two nodes each think that the other node is dead, they might both write to the same partition and cause damage to data on the shared partition.
To protect against the data damage that can be caused by two nodes writing to the same partition at the same time, you should implement node fencing or resource fencing in your cluster. Node fencing locks resources away from a node whose status is uncertain. Resource fencing ensures exclusive access to a given resource and provides finer granularity, so that a node with uncertain status can still be safely used under certain circumstances. In addition to node fencing and resource fencing, some hardware provides self-fencing resources that take care of the problem for you.
There are numerous ways to implement fencing. The following Web sites offer additional information about fencing: