Strømmirror

Strømmirror is a concept in distributed systems that describes a mechanism for maintaining real-time mirrors of a primary data stream across multiple geographically dispersed nodes. The goal is to enable low-latency access to up-to-date information while preserving the order and integrity of the original stream. The term blends "strøm," meaning stream in several Nordic languages, with "mirror."

A strømmirror setup typically comprises a source stream producer, a streaming transport layer, and multiple follower replicas. The system prefixes or encodes events with sequence numbers or timestamps, then disseminates them to followers. Followers replay events in the same order to reconstruct the exact stream locally. Depending on requirements, replication may be configured for strong consistency or designed for eventual consistency; conflict handling can involve deterministic replay, version vectors, CRDT-based merges, or last-writer-wins strategies.

Applications include real-time analytics, content delivery and edge caching, database replication, and disaster recovery. In cloud-native environments, strømmirror can complement message queues and event buses by providing continuous, ordered copies of streams for passive processing, auditing, or offline analysis. It is also relevant for synchronized caches and synchronized storage backends across regions.

Challenges include network latency and jitter, bandwidth costs, fault tolerance, cursor management, time synchronization, and security concerns such as authentication and data integrity. As a non-standard term, implementations vary widely across platforms and vendors.