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Weaviate Storage Autoscaling

This guide will give you an overview of how KubeDB autoscales the storage of a Weaviate cluster using a WeaviateAutoscaler.

Before You Begin

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

How Storage Autoscaling Works

KubeDB provides a WeaviateAutoscaler CRD to automatically expand the storage of a Weaviate cluster when the volumes start filling up. Storage autoscaling requires a StorageClass that supports volume expansion (allowVolumeExpansion: true).

The storage autoscaling process consists of the following steps:

1. The user creates a WeaviateAutoscaler CR with a spec.storage.weaviate block describing the trigger, the usage threshold, and the scaling factor.

2. The KubeDB Autoscaler operator watches the PVC usage of the Weaviate pods.

3. When a volume’s used space crosses usageThreshold (a percentage of the volume capacity), the Autoscaler operator creates a WeaviateOpsRequest of type VolumeExpansion, increasing the volume size by scalingThreshold percent.

4. The KubeDB Ops Manager applies the VolumeExpansion ops request, expanding the PVCs.

The relevant fields under spec.storage.weaviate are:

• trigger — On or Off, enables/disables storage autoscaling.
• usageThreshold — the percentage of used space that triggers expansion.
• scalingThreshold — the percentage by which the volume is expanded each time.
• expansionMode — Online or Offline.

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