Tinder’s Elasticsearch 8 migration: dual writes, reindexing, zero‑downtime
Tinder upgraded from ES 6 to ES 8 in three phases: dual writes kept data consistent across clusters, a full reindex into ES 8 ran with strict validation, and a cutover with automated rollback. Benchmarks showed up to 30% lower query latency and 20% cost savings, proving that large‑scale search can evolve without service interruption.