The eviction policy defines the methodology that Redis Enterprise Software uses when the database exceeds the memory limit. The eviction policies are:

Policy Description
 noeviction Returns an error if the memory limit has been reached when trying to insert more data
 allkeys-lru Evicts the least recently used keys out of all keys
 allkeys-lfu Evicts the least frequently used keys out of all keys
 allkeys-random Randomly evicts keys out of all keys
 volatile-lru Evicts the least recently used keys out of all 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 all keys with an “expire” field set.
Note -
  • Active-Active databases always operate in noeviction mode.
  • Review the documentation for each Redis module to see how it uses eviction.

If you want to avoid data eviction, we recommend that you use Redis on Flash (RoF). RoF stores the hot data of your dataset in RAM and the rest of your dataset in Flash memory (SSD). This lets you kept more data in your database while keeping only the most critical data in high-cost RAM.