Redis-Compatible In-Memory Databases (key-value store)

On this page you will find information on Redis-compatible in-memory databases as a managed service, which store data as keys and values (key-value store) in non-relational form.

Due to licence changes and the associated uncertainty about the future development of Redis, we have decided to offer a Redis-compatible alternative as a replacement in the near future.

Running a key-value store as a managed service is a good option if your applications are already running on managed servers. Of course, use is also possible for applications on Nine Kubernetes Engine, Kubernetes vcluster and deplo.io.

Key-Value Stores can also be obtained in self-service as On-Demand Database via the Cockpit; configuration options and limitations are described in the linked product overview.

IP/Port

By default, the instance is reachable on port 6379 and is bound to the address 127.0.0.1 and therefore cannot be called from an external system.

Persistence

To ensure that previously written keys are not lost when the service or managed server is restarted, snapshots are regularly written to the hard drive.

Memory Management

What happens if no more memory can be allocated?

A key-value store instance is allocated a quarter of the memory available on the managed server by default.

Predefined strategies set by the maxmemory_policy define what should happen when the available memory is exhausted. By default, the policy allkeys-lru is being used, which behaves as follows:

allkeys-lru: Keeps most recently used keys; removes least recently used (LRU) keys

This ensures that no data is lost during writing due to a lack of available memory. To free up the required space, keys that have not been accessed for the longest time are automatically deleted. This form of balancing is designed to ensure the highest possible availability of the application in the most variety of scenarios.

If you are familiar with your application's access patterns, are dependent on longevity of the keys or are working with TTLs and would like to use e.g. volatile-lru, please contact our support team to adjust the default configuration. An overview of all policies can be found in the Redis documentation.