redis Database Eviction Policies Redis on Flash

Database Eviction Policies - Redis Enterprise Software | Redis Labs https://redislabs.com/redis-enterprise-documentation/administering/database-operations/eviction-policy/

Eviction policies

The eviction policy designates a data eviction method for Redis Enterprise Software (RS) to use when the database size reaches its limit. You can select any of the following:

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-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-ttl	Evicts the shortest time-to-live and least recently used keys out of all keys with an “expire” field set.
volatile-random	Randomly evicts keys with an “expire” field set

One mechanism to avoid this, but still keep performance is to use Redis on Flash. It can span your database across RAM + Flash Memory and intelligently manage what data is hot and should be in RAM and what data is not and can be on Flash memory (SSD).

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