Supported instance configurations

Preview

This feature is subject to the "Pre-GA Offerings Terms" in the General Service Terms section of the Service Specific Terms. Pre-GA features are available "as is" and might have limited support. For more information, see the launch stage descriptions.

This page describes maxmemory policies and other Redis configurations available for Memorystore for Redis Cluster.

For instructions on how to modify the configurations listed on this page, see Configure an instance.

Maxmemory policies

When your instance memory is full, and a new write comes in, Redis evicts keys to make room for the write based on your instance's maxmemory policy. The default maxmemory policy for Memorystore for Redis Cluster is volatile-lru. You can also use one of the following maxmemory policies:

• noeviction: Returns an error when the instance reaches maxmemory. Does not overwrite or evict any data.
• allkeys-lfu: Evicts the least frequently used (LFU) keys from the entire keyset.
• allkeys-lru: Evicts the least recently used (LRU) keys from the entire keyset.
• volatile-lfu: Evicts the least-frequently-used keys that are set with TTL (time to live) expirations.
• volatile-lru: Evicts the least recently used (LRU) keys that are set with TTL expirations.
• allkeys-random: Evicts random keys from the entire keyspace.
• volatile-random: Evicts random keys from among those set with TTL expirations.
• volatile-ttl: Evicts the keys with the shortest TTL from among those set with TTL expirations.

Modifiable configuration parameters

You can modify the following parameters when creating or updating a Memorystore for Redis Cluster instance.

Parameter	Description	Acceptable values
maxmemory-clients	Redis 7.0, or later. This configuration allows users to control maximum memory usage of clients. Total memory usage of normal/pubsub clients. If the limit is hit, the client with most memory usage will be evicted.	Acceptable values are integer percent values between 0% and 100%. Represents the percentage of instance maxmemory to which client storage is limited.
maxmemory	Designates an adjustable limit at which your eviction policy takes effect. You set the maxmemory limit at the individual node level, but the setting applies to all nodes. For example, suppose that you have an instance with 3 nodes, use a 58 GB redis-highmem-xlarge node type, and want to set maxmemory to 90% of your total instance capacity. To do this, you set maxmemory to 52.2 GB, which is 90% of your node capacity. This applies to all nodes, which sets the total instance maxmemory limit at 90%. For more information about default reserved overhead, see keyspace capacity and reserved overhead.	Maxmemory limit for your instance. It supports the following units: b (default) k kb m mb g gb
maxmemory-policy	Specifies the behavior Redis follows when the instance data reaches the maxmemory limit. For more information about each policy, see Maxmemory policies . For additional information about the open source Redis maxmemory policies, see the open source Redis LRU cache page.	noeviction allkeys-lru volatile-lru (default) allkeys-random volatile-random volatile-ttl volatile-lfu (Redis version 4.0 and higher) allkeys-lfu (Redis version 4.0 and higher)
notify-keyspace-events	Allows clients to subscribe to notifications on certain keyspace events. For more information, see Redis Keyspace Notifications.	"" No event (default) K Keyspace events, published with __keyspace@<db>__ prefix. E Keyevent events, published with __keyevent@<db>__ prefix. g Generic commands (non-type specific) like DEL, EXPIRE, or RENAME $ String commands l List commands s Set commands h Hash commands z Sorted set commands x Expired events (events generated every time a key expires) e Evicted events (events generated when a key is evicted for maxmemory) A Alias for g$lshzxe, so that the "AKE" string means all the events.
slowlog-log-slower-than	Lets you configure the slow log. Specifies the execution time threshold (in microseconds). Whenever a command exceeds this threshold, it is added to the slow log.	Default value is 10000. A value of zero forces the logging of every command. Whereas, a value of -1 disables the slow log. Any other negative value is rejected.
maxclients	Lets you configure the maxclients configuration for your instance. For information about the max clients limit and default for your instance, see Max clients.	Default value depends on the node type. For more information, see Node characteristics.