UltraWarm is a fully managed, warm storage tier that’s designed to deliver cost savings on the Amazon OpenSearch Service. With OpenSearch 2.17+ domains, you can now store k-NN (vector) indexes on UltraWarm storage reducing the cost of serving infrequently access k-NN indexes through warm and cold storage tiers. With UltraWarm storage, you can further cost optimize vector search workloads on the OpenSearch vector engine. To learn more, refer to the documentation.
Source:: Amazon AWS