Use Redis on Flash on Kubernetes

Prerequisites

Redis Enterprise Software for Kubernetes supports using Redis on Flash, which extends your node memory to use both RAM and flash storage. SSDs (solid state drives) can store infrequently used (warm) values while your keys and frequently used (hot) values are still stored in RAM. This improves performance and lowers costs for large datasets.

Before creating your Redis clusters or databases, these SSDs must be:

• locally attached to worker nodes in your Kubernetes cluster
• formatted and mounted on the nodes that will run Redis Enterprise pods
• dedicated to RoF and not shared with other parts of the database, (e.g. durability, binaries)
• provisioned as local persistent volumes
  • You can use a local volume provisioner to do this dynamically
• a StorageClass resource with a unique name

For more information on node storage, see Node persistent and ephemeral storage.

Create a Redis Enterprise cluster

To deploy a Redis Enterprise cluster (REC) with flash storage, you’ll need to specify the following in the redisOnFlashSpec section of your REC custom resource:

• enable Redis on Flash (enabled: true)
• flash storage driver (flashStorageEngine)
  • The only supported value is rocksdb
• storage class name (storageClassName)
• minimal flash disk size (flashDiskSize)

Here is an example of an REC custom resource with these attributes:

apiVersion: app.redislabs.com/v1
kind: RedisEnterpriseCluster
metadata:
  name: "rec"
spec:
  
  nodes: 3
  redisOnFlashSpec:
    enabled: true
    flashStorageEngine: rocksdb
    storageClassName: local-scsi
    flashDiskSize: 100G

Create a Redis Enterprise database

By default, any new database will use RAM only. To create a Redis Enterprise database (REDB) that can use flash storage, specify the following in the redisEnterpriseCluster section of the REDB custom resource definition:

• isRof: true enables Redis on Flash
• rofRamSize defines the RAM capacity for the database

Below is an example REDB custom resource:

apiVersion: app.redislabs.com/v1alpha1
kind: RedisEnterpriseDatabase
metadata:
  name: rof-redb
spec:
  redisEnterpriseCluster:
    name: rec
  isRof: true
  memorySize: 2GB
  rofRamSize: 0.5GB