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Weaviate StorageClass Migration

This guide will give you an overview of how KubeDB Ops Manager migrates a Weaviate cluster from one StorageClass to another.

Before You Begin

• You should be familiar with the following KubeDB concepts:
  • Weaviate
  • Weaviate Quickstart

How Storage Migration Process Works

Storage migration moves the data of a Weaviate cluster from its current StorageClass onto a new one — for example, migrating from a cloud-provider block storage to Longhorn, or vice-versa.

The storage migration process consists of the following steps:

1. The user creates a WeaviateOpsRequest CR of type StorageMigration referencing the Weaviate database. The spec.migration field specifies the target storageClassName and the reclaim policy (oldPVReclaimPolicy) to apply to the old PersistentVolumes.

2. KubeDB Ops Manager watches for the WeaviateOpsRequest CR and halts the Weaviate object.

3. For each node, the Ops Manager provisions a new PVC on the target StorageClass, copies the data from the old volume to the new volume, and re-points the node at the new volume.

4. The old PersistentVolumes are handled according to spec.migration.oldPVReclaimPolicy (for example Delete).

5. The Ops Manager updates the Weaviate object’s spec.storage.storageClassName to the new StorageClass and resumes the Weaviate object so that the KubeDB Provisioner operator resumes its usual operations.

Note: The target StorageClass must be different from the current one. If the database is already running on the target StorageClass, there is nothing to migrate.

In the next doc, we are going to show a step-by-step guide on migrating the StorageClass of a Weaviate cluster.