Cross-regional Level of Memcache
Explore the key challenges in scaling Memcache across global regions, including latency, data replication lag, and consistency. Learn how to maintain read-after-write semantics using primary-secondary replication and invalidation mechanisms. Understand the trade-offs between availability and consistency in cross-regional caches and how these affect user experience.
Introduction to the cross-regional level
At the regional level, latency was not a huge problem as the latencies inside a data center are around one millisecond, but as soon as we go to the cross-regional level, the latencies might go to around a 100 milliseconds. Due to this, and unlike in previous layers the CAP theorem comes in full effect and we have to choose between availability and consistency.
Cross-regional replication brings many benefits to our system:
Firstly, it reduces latency by allowing clients to communicate with local Memcached and database servers.
Secondly, it can ...