What is cache coherency in distributed systems?

What is cache coherency in distributed systems?

Cache coherency refers to the consistency of data stored in local caches of a distributed system. It ensures that any changes made to a data item in one cache are reflected in all other caches that store that data.

Why is cache coherency important?

It's crucial because it prevents data inconsistency and ensures that all nodes in a distributed system have a unified view of the data, which is essential for maintaining system integrity and performance.

What are some common protocols used for maintaining cache coherency?

Common protocols include MESI (Modified, Exclusive, Shared, Invalid), MOESI, and MSI. These protocols help manage how caches communicate and update their data.

Can you explain the MESI protocol?

Sure! The MESI protocol uses four states for cache lines: Modified, Exclusive, Shared, and Invalid. It helps manage the sharing of data between caches while minimizing the number of times data is fetched from the main memory.

What challenges do distributed systems face with cache coherency?

Challenges include increased latency, network overhead, and the complexity of ensuring consistency across multiple caches, especially in large-scale systems.