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Redis Displacement Policies
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Redis Displacement Policies

The maxmemory-policy is an algorithm by which Redis frees memory when its actual utilization in the cluster reaches the maximum available memory (maxmemory).

The maxmemory value is 75% of RAM (the other 25% is reserved for service processes).

Selecting a preemptive policy can be done by cluster creation or modify in the created cluster.

List of policies⁠

  • volatile-lru — removes expired keys using the approximated LRU algorithm;
  • allkeys-lru- removes any key using the approximated LRU algorithm;
  • volatile-lfu — removes expired keys using the approximated LFU algorithm;
  • allkeys-lfu — removes any key using the approximated LFU algorithm;
  • volatile-random — removes a random key with expired validity;
  • allkeys-rando — removes any random key;
  • volatile-ttl — removes a key with a shorter lifetime (smaller TTL);
  • noeviction — does not delete keys, just returns an error on write operations.

Change the displacement policy⁠

When you change the policy, the key deletion rules change.

For your information

We recommend changing the policy only if you are sure what it will affect — there is a possibility of losing some data.

  1. In control panel go to Cloud platform → Databases.
  2. Open the cluster page → tab Settings.
  3. In the block Displacement policy click Modify and select a new algorithm.