Partition tolerance

There are times when a system may become partially disconnected from itself. Consider a system that is spread between two physical locations and is replicating data back and forth; that system may suffer a partitioning through events such as a network outage. In these cases, the degree to which the system can continue functioning is its partition tolerance. For example, some systems may become partially read-only (often times the smaller partition), where other systems may be able to operate independently and then re-synchronize when they re-join.