Fix Memory Full in Redis: Cache Error Solution (2026)
How to Fix “Memory Full” in Redis (2026 Guide) The Short Answer To fix the “Memory Full” error in Redis, adjust the eviction policy to remove less recently used (LRU) keys when the memory limit is reached, which can be done by setting the maxmemory-policy configuration option to allkeys-lru. This change can reduce the memory usage from 100% to 80% within 10 minutes, depending on the workload and configuration. Why This Error Happens Reason 1: The most common cause of the “Memory Full” error in Redis is when the maxmemory limit is reached, and the eviction policy is not set to remove keys, resulting in a cache error. For example, if the maxmemory limit is set to 4GB and the Redis instance is handling 10,000 requests per minute, the memory usage can increase rapidly, leading to the error. Reason 2: An edge case cause of this error is when the Redis instance is configured to use a custom eviction policy that is not suitable for the specific use case, such as using the volatile-lru policy with a high number of persistent keys. This can lead to a situation where the Redis instance is unable to evict keys, resulting in the “Memory Full” error. Impact: The “Memory Full” error can cause a cache error, leading to a significant decrease in performance and potentially resulting in errors for users. For instance, if the Redis instance is used as a cache layer for a web application, the error can cause the application to slow down or become unresponsive, leading to a poor user experience. Step-by-Step Solutions Method 1: The Quick Fix Go to Redis Config > Memory and set the maxmemory limit to a lower value, such as 2GB, to reduce the memory usage. Toggle the maxmemory-policy option to allkeys-lru to enable the eviction of less recently used keys when the memory limit is reached. Refresh the Redis instance to apply the changes. Method 2: The Command Line/Advanced Fix To configure the eviction policy using the Redis command line, run the following command: ...