Snapshot algorithm
A snapshot algorithm (ger .: snapshot algorithm ), including: distributed snapshot serves a consistent state of a distributed system to store. Since there is generally no shared memory and no shared time, this is not possible in a trivial way.
example
Several computers work together in a distributed system, each representing an account. Messages can be used to transfer amounts from one account to another.
The sum of the account balances is to be determined. If the account balance were only queried from each computer, the result can be incorrect if a computer has sent a transfer (and thus reduced its account balance), but it has not yet reached the recipient. A snapshot algorithm resolves such inconsistencies.