Memory Architecture in Redis Enterprise Software
Redis Enterprise Software has multiple memory mechanisms in its architecture, from RAM to Flash Memory, to having databases that span them both.
By default, RS manages node memory so that data is entirely in RAM for improved database performance. RS is designed to handle memory management to optimize database performance - better than OS memory management. If not enough RAM is available, RS prevents adding more data into the databases. RS protects the existing data and prevents the database from being able to store data into the shards. It can be configured to move the data to another node, or even discard it.
Redis on Flash (RoF) offers users of Redis Enterprise Software and Redis Enterprise VPC the unique ability to have very large Redis databases but at significant cost savings. Where standard Redis databases must all be in RAM, Redis on Flash enables your Redis databases to span both RAM and dedicated flash memory (SSD). Whilst keys are always stored in RAM, RoF intelligently manages the location of their values (RAM vs Flash) in the database via a LRU-based (least-recently-used) mechanism.