For each database, you can choose from these data eviction policies:

Options Description
allkeys-lru Evicts the least recently used (LRU) keys out of all keys in the database
allkeys-lfu Evicts the least frequently used keys out of all keys
allkeys-random Randomly evicts keys out of all keys in the database
volatile-lru (default) Evicts the least recently used (LRU) keys out of keys with an "expire" field set
volatile-lfu Evicts the least frequently used keys out of all keys with an "expire" field set
volatile-random Randomly evicts keys with an "expire" field set
volatile-ttl Evicts the shortest time-to-live and least recently used keys out of keys with an "expire" field set
no eviction Returns error if memory limit has been reached when trying to insert more data

Redis Cloud supports Redis on Flash (RoF) to prevent data eviction but maintain high performance. RoF can span your database across RAM and Flash Memory and intelligently manage hot data in RAM and cold data in Flash memory (SSD).

Note -
Active-Active Geo-Distributed CRDBs always operates in noeviction mode.