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Configure auto-tiering for Google Cloud NetApp Volumes

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This page describes how to configure auto-tiering for Google Cloud NetApp Volumes using Trident.
Auto-tiering is configured through Trident backend parameters and PersistentVolumeClaim annotations during volume provisioning.

Overview

Auto-tiering allows Trident to provision volumes that automatically move inactive data from a performance tier to a capacity tier.
This reduces storage cost while preserving performance for frequently accessed data.

Trident applies auto-tiering settings only at volume creation time.
Post-provisioning changes are not supported in Trident 26.02.

Concepts

Auto-tiering

Auto-tiering moves infrequently accessed data from a performance tier to a capacity tier based on access patterns.
Data movement occurs asynchronously and is not immediate.

Tiering policy

The tiering policy determines whether auto-tiering is enabled for a volume.

The following policies are supported:
* auto: Enables automatic tiering based on access patterns
* none: Disables auto-tiering

Cooling days

Cooling days specify the minimum number of days a block of data must remain inactive before it becomes eligible for tiering.
Cooling days apply only when the tiering policy is set to auto.

Configuration model

Configuration scopes

Auto-tiering can be configured at multiple scopes:

  • Storage pool scope
    Applies to all volumes provisioned from the pool.

  • Volume scope
    Applies to a single volume through PersistentVolumeClaim annotations.

Trident determines the effective configuration based on where each setting is defined.

Configuration precedence

When the same setting is defined at multiple scopes, Trident applies the following precedence order:

  1. PersistentVolumeClaim annotations

  2. Trident backend configuration

  3. Storage pool defaults

Settings defined at a higher precedence override lower-level values.

Supported functionality in Trident 26.02

Trident 26.02 supports the following auto-tiering capabilities for Google Cloud NetApp Volumes:

  • Enabling or disabling auto-tiering during volume provisioning

  • Defining a tiering policy in the Trident backend configuration

  • Overriding the tiering policy and cooling days per volume using PVC annotations

  • Configuring cooling days for volumes with auto-tiering enabled

Unsupported functionality in Trident 26.02

The following operations are not supported:

  • Modifying auto-tiering settings after volume creation

  • Changing tiering policies on existing volumes using Kubernetes updates

  • Applying auto-tiering settings outside of Trident-managed provisioning workflows

Backend configuration parameters

The following parameters control auto-tiering behavior when defined in the Trident backend configuration:

Parameter Required Description

tieringPolicy

No

Tiering policy for volumes (auto or none)

tieringMinimumCoolingDays

No

Number of inactive days before data is tiered (range: 2–183, default: 31)

Volume-level overrides using PersistentVolumeClaim annotations

Supported annotations

PersistentVolumeClaim annotations allow per-volume overrides of auto-tiering settings.

Annotation Description

trident.netapp.io/tieringPolicy

Overrides the tiering policy for the volume

trident.netapp.io/tieringMinimumCoolingDays

Overrides the cooling days value for the volume

Example: PersistentVolumeClaim with auto-tiering overrides

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: auto-tiering-pvc
  annotations:
    trident.netapp.io/tieringPolicy: auto
    trident.netapp.io/tieringMinimumCoolingDays: "45"
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: google-cloud-netapp-volumes-auto-tiering
  resources:
    requests:
      storage: 500Gi

Behavior and limitations

Provisioning behavior

  • Auto-tiering settings are evaluated and applied only at volume creation time.

  • Trident does not reconcile tiering configuration after provisioning.

  • Cooling days are ignored when the tiering policy is set to none.

Platform limitations

  • Auto-tiering is supported only for NAS volumes (NFS and SMB).

  • Block volumes (iSCSI) do not support auto-tiering.

  • The Google Cloud NetApp Volumes storage pool must have auto-tiering enabled in Google Cloud.

Supported values

  • Valid range for tieringMinimumCoolingDays: 2 to 183

  • Default value: 31