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Milvus Storage Autoscaling

This guide will show you how to use the KubeDB Autoscaler operator to autoscale the persistent storage of a Milvus database.

Before You Begin

• You should be familiar with the following KubeDB concepts:

  • Milvus
  • MilvusAutoscaler
  • Storage Autoscaling Overview

• Install the KubeDB Autoscaler operator and Prometheus (storage autoscaling reads PVC usage from Prometheus).

• The PVC’s StorageClass must support volume expansion (allowVolumeExpansion: true) — e.g. longhorn-custom.

• Complete the dependency setup from Prepare Dependencies. It installs MinIO, creates the my-release-minio secret, and installs the etcd operator required by Milvus.

Note: The yaml files used in this tutorial are stored in docs/guides/milvus/autoscaler/storage/yamls folder in GitHub repository kubedb/docs.

Storage Autoscaling — Standalone Milvus

Deploy a standalone Milvus on an expansion-capable StorageClass and create a MilvusAutoscaler targeting the standalone node:

storage-standalone.yaml

apiVersion: autoscaling.kubedb.com/v1alpha1
kind: MilvusAutoscaler
metadata:
  name: milvus-storage-autoscaler
  namespace: demo
spec:
  databaseRef:
    name: milvus-standalone
  storage:
    node:
      trigger: "On"
      usageThreshold: 30
      expansionMode: "Offline"
      scalingRules:
        - appliesUpto: "100Ti"
          threshold: "50%"
  opsRequestOptions:
    apply: IfReady
    timeout: 10m

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.7.10/docs/guides/milvus/autoscaler/storage/yamls/storage-standalone.yaml
milvusautoscaler.autoscaling.kubedb.com/milvus-storage-autoscaler created

When the volume usage crosses usageThreshold (30%), the autoscaler creates a VolumeExpansion MilvusOpsRequest sized per scalingRules.

$ kubectl get milvusautoscaler -n demo
NAME                                   AGE
milvus-standalone-compute-autoscaler   94s
milvus-storage-autoscaler              93s

The storage autoscaler watches the streamingnode/node PVC usage (read from Prometheus). When usage crosses usageThreshold, it creates a VolumeExpansion MilvusOpsRequest. In this walkthrough the volume stayed well below the threshold (a freshly-created, near-empty 1Gi volume), so no expansion was triggered:

$ kubectl get pvc -n demo -l app.kubernetes.io/instance=milvus-standalone -o custom-columns=NAME:.metadata.name,SIZE:.status.capacity.storage
NAME                       SIZE
data-milvus-standalone-0   1Gi

To see the expansion fire, write enough data to push PVC usage past usageThreshold (30% here). When it does, the autoscaler creates a VolumeExpansion MilvusOpsRequest (with expansionMode as configured), which the Ops-manager applies — see the volume expansion guide for the resulting flow and output.

Storage Autoscaling — Distributed Milvus

For a distributed Milvus, storage autoscaling targets streamingnode — the only distributed role with a persistent volume:

storage-distributed.yaml

apiVersion: autoscaling.kubedb.com/v1alpha1
kind: MilvusAutoscaler
metadata:
  name: milvus-storage-autoscaler
  namespace: demo
spec:
  databaseRef:
    name: milvus-cluster
  storage:
    streamingnode:
      trigger: "On"
      usageThreshold: 34
      expansionMode: "Online"
      scalingRules:
        - appliesUpto: "100Ti"
          threshold: "50%"
  opsRequestOptions:
    apply: IfReady
    timeout: 10m

Because only streamingnode carries a persistent volume among the distributed roles, storage autoscaling targets streamingnode exclusively. When the streamingnode PVC usage crosses usageThreshold (34% here), the autoscaler creates a VolumeExpansion MilvusOpsRequest against streamingnode (expansionMode: Online), which the Ops-manager applies as shown in the volume expansion guide.

Cleaning up

$ kubectl delete milvusautoscaler -n demo --all
$ kubectl delete milvus.kubedb.com -n demo milvus-standalone
$ kubectl delete ns demo

Next Steps

• Learn about compute autoscaling.
• Want to hack on KubeDB? Check our contribution guidelines.