Storage

This chapter describes Hazelcast's High-Density Memory Store and its configuration and provides information on the High-Density Memory First Generation, also known as Hazelcast Elastic Memory. It also gives recommendations on the storage sizing.

High-Density Memory Store

Hazelcast High-Density Memory Store, the successor to Hazelcast Elastic Memory, is Hazelcast's new enterprise grade backend storage solution. This solution is used by JCache and IMap implementations.

By default, Hazelcast offers a production ready, low garbage collection (GC) pressure, storage backend. Serialized keys and values are still stored in the standard Java map, such as data structures on the heap. The data structures are stored in serialized form for the highest data compaction, and are still subject to Java Garbage Collection.

In Hazelcast Enterprise, the High-Density Memory Store is built around a pluggable memory manager which enables multiple memory stores. These memory stores are all accessible using a common access layer that scales up to Terabytes of main memory on a single JVM. At the same time, by further minimizing the GC pressure, High-Density Memory Store enables predictable application scaling and boosts performance and latency while minimizing pauses for Java Garbage Collection.

This foundation includes, but is not limited to, storing keys and values next to the heap in a native memory region.

RELATED INFORMATION

Please refer to the Hazelcast JCache chapter for the details of Hazelcast JCache implementation. As mentioned, High-Density Memory Store is used with Hazelcast JCache implementation.