Storage classes reference

Every StorageClass on the cluster in one table. Use it to check which provisioner backs a class, whether it can grow, and what happens to the data when a PVC is deleted.

The classes#

standard is present and set as default on every cluster. The local-* classes appear once you install TopoLVM , and juicefs appears once you install the JuiceFS CSI driver . List what your cluster has right now:

		$ kubectl get storageclasses
NAME                 PROVISIONER         RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
local-hdd            topolvm.io          Retain          WaitForFirstConsumer   true                   10d
local-nvme           topolvm.io          Retain          WaitForFirstConsumer   true                   10d
local-ssd            topolvm.io          Retain          WaitForFirstConsumer   true                   10d
standard (default)   csi.hetzner.cloud   Retain          WaitForFirstConsumer   true                   10d
	

Reading the columns#

Access modes decide how many nodes can mount a volume. The block and local classes are ReadWriteOnce; only juicefs offers ReadWriteMany. See Access modes and volume binding .

Binding is when the volume is created. WaitForFirstConsumer waits for a pod so the volume lands where the pod runs. Immediate creates it as soon as the PVC exists, which suits object-backed storage that has no location to match.

Reclaim is Retain on every class, on purpose. Deleting a PVC deletes the Kubernetes object, not the data behind it: the underlying volume is kept, not erased. Syself would rather a mistaken delete leave your data intact than let one command wipe it.

The flip side is that cleanup is a deliberate act. A Hetzner Cloud volume keeps costing money until you delete it yourself, and a local volume keeps holding pool space until you remove it. See Volume attach constraints and reclaim policies and Local PV lifecycle for how to reclaim the space when you mean to.

Expandable means you can grow a volume by editing the PVC. Every class allows expansion. Volumes only grow, they never shrink. See Expand a Hetzner Cloud volume .

Backed by is the storage behind each class. standard is Hetzner Cloud volumes on cloud nodes: each volume sits on Ceph with three copies, so losing a disk does not lose the data. Hetzner attaches at most 16 volumes to one server, so plan for that ceiling on a volume-heavy node. The local-* classes are disks inside one bare metal server and carry no built-in redundancy, so keep the data replicated in the app.

The default class and how to change it#

A PVC with no storageClassName uses the default class, marked (default) in the list above.

		$ kubectl get storageclass standard -o jsonpath='{.metadata.annotations.storageclass\.kubernetes\.io/is-default-class}'
true
	

To make a different class the default, clear the flag on the current one and set it on the new one:

		$ kubectl patch storageclass standard -p '{"metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}'
	

		$ kubectl patch storageclass local-nvme -p '{"metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'