Use persistent volumes in Redis Enterprise clusters

This section covers details about how persistent volumes are sized and specified for Redis Enterprise cluster deployments.

Storage types

Redis Enterprise for Kubernetes can only use storage classes supported by block storage. Block storage is mounted at the Kubernetes node level and utilizes EXT4 or XFS file systems. It can be sourced from enterprise-grade SANs or cloud environments such as EBS, Azure Managed Disks, or GCP persistent disks.

REC persistentSpec field

To deploy a Redis Enterprise cluster with Redis Enterprise operator the spec should include a persistentSpec section, in the redis-enterprise-cluster.yaml file:

spec:
  nodes: 3
  persistentSpec:
   enabled: true
   storageClassName: "standard"
   volumeSize: "23Gi” #optional

Persistence storage is a requirement for production deployments.

Volume size

volumeSize is an optional definition. By default, if the definition is omitted, operator allocates five times (5x) the amount of memory (RAM) defined for nodes (see example below), which is the recommended persistent storage size as described in the Hardware requirements article.

To explicitly specify the persistent storage size, use the volumeSize property as described in the example above.

Persistent volume claims can be expanded, but not reduced after creation. See Expand PersistentVolumeClaim (PVC) for details.

Storage class name

storageClassName determines the Storage Class resource, which is defined by the Kubernetes cluster administrator, to be used for persistent storage.

Different Kubernetes distributions and different deployments use different Storage Class resources.

In order to determine the Storage Class resources available for your K8s deployment, use the following command:

kubectl get StorageClass

Typically, AWS provides “gp2” as the Storage Class name while GKE uses “standard.” Azure provides two Storage Classes: "default" using HDDs, and "managed-premium" using SSDs.

Below is an example of a response to the command.

Example of the redisEnterpriseNodeResources definition:

redisEnterpriseNodeResources:
  limits:
    cpu: “4000m”
    memory: 4Gi
  requests:
    cpu: “4000m”
    memory: 4Gi