A snapshot algorithm is used to create a consistent snapshot of the global state of a

distributed system A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer sci ...

. Due to the lack of globally shared memory and a global clock, this is not trivially possible.

Example

Several computers work together in a distributed system. Each of them represents a bank account holding a certain amount of money. The participants can transfer money between their accounts by exchanging the messages. Assume the overall balance shall be calculated. Just requesting the balance of each participant can lead to an incorrect result, if one of them just sent a transfer message to another one (and thus has already decreased its own balance), which did not yet receive it. A snapshot algorithm avoids such inconsistencies.

Algorithms

Chandy–Lamport algorithm The Chandy–Lamport algorithm is a snapshot algorithm that is used in distributed systems for recording a consistent global state of an asynchronous system. It was developed by and named after Leslie Lamport and K. Mani Chandy. Leslie Lamport, K. ...

* Lai–Yang algorithm * Spezialetti–Kearns algorithm * Mattern's algorithm

References

{{Reflist Distributed algorithms