1. Cache and Data Consistency in Distributed systems (CAP/PACELC/CRDT)
moved to: https://software.mihvoi.ro/2026/04/1-cache-and-data-consistency-in.html Abstract There is always a tension between data C onsistency and system A vailability when P artitioning a system across datacenters (think CAP ). Especially data cache-ing poses interesting challenges. This tension becomes way more acute as soon you have 2 data centers separated by more than 10ms latency. I present below some of the problems along with possible solutions. In the end I will present an elegant solution that maximizes A vailability while providing the needed C onsistency level for read-after-writes flows. The solution requires the client to carry a monotonic id along the flow. I would postulate that any solution where the client don't carry some consistency info will provide a higher latency that the presented solution (see chapter "Flow consistency" ) . The examples below are simplified to be intuitive and easy to understand, however the...