In Memory Storage Backends

All of the primary storage backends for Titan persist the data durably to disk.
This is has two primary benefits:

• Parts of the graph that are not accessed frequently can be held on disk and not in RAM which significantly reduces the cost of storing large graphs.
• The data is persisted durably and can be recovered in case of single machine failure.

However, if the entire graph is frequently accessed and low latency access is required, Titan additionally supports in-memory storage backends. Those hold all data in-memory and thereby avoid the additional complexities and access cost of disks.

In-Memory Storage Backend Overview

Name	storage.option	Consistency	Availability	Scalability	Replication	Persistence
Hazelcast	hazelcast	transactional consistency	highly available	linear scalability	yes	in-memory
Infinispan	infinispan	transactional consistency	highly available	linear scalability	yes	in-memory