AWS announces durability support for Amazon ElastiCache for Valkey, enabling it to serve as a persistent data store in addition to a cache. Two modes are available: synchronous writes (zero data loss, single-digit millisecond write latency, data persisted across at least two AZs before acknowledging) and asynchronous writes (microsecond write latency, up to 10 seconds of potential data loss, no additional cost). Both modes preserve microsecond read latency. Performance benchmarks on r7g.4xlarge nodes at 50K and 100K TPS show asynchronous writes match non-durable ElastiCache performance, while synchronous writes add write latency but keep reads sub-millisecond. The feature uses a Multi-AZ transactional log and is available starting with Valkey 9.0 across all AWS commercial, China, and GovCloud regions.
