Chapter 2. Storage classes and storage pools

The OpenShift Container Storage operator installs a default storage class depending on the platform in use. This default storage class is owned and controlled by the operator and it cannot be deleted or modified. However, you can create a custom storage class if you want the storage class to have a different behavior.

You can create multiple storage pools which map to storage classes that provide the following features:

  • Enable applications with their own high availability to use persistent volumes with two replicas, potentially improving application performance.
  • Save space for persistent volume claims using storage classes with compression enabled.
Note

Custom storage classes are not supported for external mode OpenShift Container Storage clusters.

Note

With a minimal cluster of a single device set, only two new storage classes can be created. Every storage cluster expansion allows two new additional storage classes.

2.1. Creating storage classes and pools

You can create a storage class using an existing pool or you can create a new pool for the storage class while creating it.

Prerequisites

Ensure that the OpenShift Container Storage cluster is in Ready state.

Procedure

  1. Log in to OpenShift Web Console.
  2. Click Storage → Storage Classes.
  3. Click Create Storage Class.
  4. Enter the storage class Name and Description.
  5. Select either Delete or Retain for the Reclaim Policy. By default, Delete is selected.
  6. Select RBD Provisioner which is the plugin used for provisioning the persistent volumes.

  7. You can either create a new pool or use an existing one.

    Create a new pool
    1. Enter a name for the pool.
    2. Choose 2-way-Replication or 3-way-Replication as the Data Protection Policy.

    3. Select Enable compression if you need to compress the data.

      Enabling compression can impact application performance and might prove ineffective when data to be written is already compressed or encrypted. Data written before enabling compression will not be compressed.

    4. Click Create to create the storage pool.
    5. Click Finish after the pool is created.
    6. Click Create to create the storage class.
    Use an existing pool
    1. Choose a pool from the list.
    2. Click Create to create the storage class with the selected pool.