Redis Eviction Policies

An eviction policy is a rule by which Redis evicts keys to free up memory when its consumption reaches a set limit. Read more about eviction policies in the Key eviction section of the Redis documentation.

You can view the list of eviction policies.

You can select an eviction policy when creating a cluster or change it in an existing cluster.

Memory limit for key storage

The memory limit for key storage is set using the maxmemory parameter. The default maxmemory value is 75% of the RAM on the cluster node. The remaining 25% is strictly reserved for Redis internal mechanisms.

You can change the maxmemory value only in Redis version 8:

• when creating a cluster;
• or when changing the eviction policy in an existing cluster.

You can change the value within the range of 1% to 75%. If you specify a value less than 75%, the remaining memory may be used by Redis internal mechanisms.

List of eviction policies

noeviction	Does not evict keys when the limit specified in maxmemory is reached. New write operations will fail due to an out-of-memory error
volatile-lru	Evicts keys with an assigned TTL that have not been accessed for a long time. Keys are evicted using the approximate LRU algorithm (Least Recently Used)
volatile-lfu	Evicts keys with a TTL that have been accessed least frequently since the TTL was set. Keys are evicted using the approximate LFU algorithm
volatile-ttl	Evicts keys with the shortest remaining TTL
volatile-random	Evicts random keys with TTL
allkeys-lru	Evicts any keys that have not been accessed for a long time. Keys are evicted using the approximate LRU algorithm
allkeys-lfu	Evicts any keys that have been accessed least frequently since they were created. Keys are evicted using the approximate LFU algorithm
allkeys-random	Evicts any random keys

Change the Eviction policy

For your information

We recommend changing the policy only if you are sure about the consequences — there is a possibility of partial data loss.

Redis 6

1. In the Dashboard, on the top menu, click Products and select Managed Databases.
2. In the Databases section, open the Active tab.
3. Open the cluster page → Settings tab.
4. In the Eviction Policy block, click Change.
5. In the Maxmemory Policy field, select an eviction policy.
6. Click Save.

Redis 8

1. In the Dashboard, on the top menu, click Products and select Managed Databases.
2. In the Databases section, open the Active tab.
3. Open the cluster page → Settings tab.
4. In the Eviction Policy block, click Change.
5. In the Maxmemory field, specify the parameter value. Available values are from 1% to 75%.
6. In the Maxmemory Policy field, select an eviction policy.
7. Click Save.