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noctarius merged 2 commits into from
Aug 21, 2026
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Clarify Pool-generated StorageClass parameters, drop dead ndcs/npcs #194

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docs: clarify Pool-generated StorageClass parameters and drop dead nd…
boddumanohar Aug 11, 2026
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docs: document the storageClassParameters to StorageClass parameter m…
noctarius Aug 21, 2026
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12 changes: 10 additions & 2 deletions docs/kubernetes/installation/k8s-storage-plane.md
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Expand Up @@ -204,8 +204,16 @@ Once the pool is active, the operator automatically creates a StorageClass named
`simplyblock-<namespace>-<clusterName>-<poolName>`. In this example, the StorageClass is called
`simplyblock-simplyblock-cluster-production-pool`.

The StorageClass is automatically removed when the storage pool is deleted. For full details and customization options
are available at [Simplyblock Operator: Storage Pool](../../reference/operator/reference.md#storagepool).
`cluster_id` and `pool_name` are set from the storage pool and cannot be overridden. The remaining StorageClass
parameters are copied from `spec.storageClassParameters`. See
[Storage Class: StorageClass Created by a Storage Pool](../usage/storage-class.md#storageclass-created-by-a-storage-pool)
for the full parameter mapping.

A StorageClass's parameters cannot be changed after creation, so `spec.storageClassParameters` is immutable
once the storage pool is created. A new storage pool is required to provision volumes with different defaults.

The StorageClass is automatically removed when the storage pool is deleted. Full details and customization
options are available at [Simplyblock Operator: Storage Pool](../../reference/operator/reference.md#storagepool).

```bash title="Check the StorageClass"
kubectl get storageclass simplyblock-simplyblock-production-my-pool
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41 changes: 37 additions & 4 deletions docs/kubernetes/usage/storage-class.md
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Expand Up @@ -24,6 +24,40 @@ simplyblock control plane to provision a logical volume matching the requested s
the complexity of volume creation and ensures that workloads running in Kubernetes receive high-performance, resilient
block storage directly backed by simplyblock.

## StorageClass Created by a Storage Pool

A StorageClass named `simplyblock-<namespace>-<clusterName>-<poolName>` is created automatically by the operator once
a `StoragePool` resource becomes active, as described in
[Create a Storage Pool](../installation/k8s-storage-plane.md#create-a-storage-pool). `cluster_id` and `pool_name` are
always set from the storage pool and cannot be overridden. The rest of the parameters are copied from
`StoragePool.spec.storageClassParameters`. Defaults for each field are listed at
[Simplyblock Operator: StorageClassParameters](../../reference/operator/reference.md#storageclassparameters).

The CRD fields carry camel case names and are written to the StorageClass under the parameter names of the CSI driver:

| `storageClassParameters` Field | StorageClass Parameter |
|--------------------------------|-----------------------------|
| `qosRwIops` | `qos_rw_iops` |
| `qosRwMbytes` | `qos_rw_mbytes` |
| `qosRMbytes` | `qos_r_mbytes` |
| `qosWMbytes` | `qos_w_mbytes` |
| `compression` | `compression` |
| `encryption` | `encryption` |
| `replicate` | `replicate` |
| `lvolPriorityClass` | `lvol_priority_class` |
| `fabric` | `fabric` |
| `maxNamespacePerSubsys` | `max_namespace_per_subsys` |
| `tune2fsReservedBlocks` | `tune2fs_reserved_blocks` |
| `filesystem` | `csi.storage.k8s.io/fstype` |

For a storage pool with `dhchap` enabled and `allowedNodes` set, `dhchap_node_label` is added by the operator as well,
and the generated StorageClass is restricted to those nodes through its allowed topologies.

Kubernetes does not allow the `parameters` of a StorageClass to be changed after creation, so
`StoragePool.spec.storageClassParameters` is immutable once the storage pool is created. There is no supported way to
reconfigure the generated StorageClass afterward. A new storage pool has to be created to provision volumes with
different defaults.

## Example Usage

A typical simplyblock StorageClass contains the name of the storage class, a filesystem type to automatically format
Expand All @@ -47,8 +81,8 @@ allowVolumeExpansion: true

## StorageClass Parameters

Each cluster has a default schema, but each volume can optionally use an alternative schema. However, the schema must
"fit" into the cluster, meaning `n+k` must be equal to (or better smaller) than the number of nodes in the cluster.
The erasure coding schema (the number of data and parity chunks per stripe) is set once at cluster creation and
applies to all volumes in the cluster. It cannot be configured per volume or through a StorageClass.

See the [Erasure Coding Configuration](../../deployment-preparation/erasure-coding-scheme.md) for more details.

Expand Down Expand Up @@ -78,8 +112,7 @@ If `namespace-volumes` is set to `yes`, the number of namespaces per subsystem h
| qos_w_mbytes | int | Defines the maximum write throughput in megabytes reserved for a logical volume of this storage class. A zero (0) means no maximum. | true | 0 |
| compression | bool | Defines if the logical volume of this storage class will be stored compressed or not. | true | false |
| encryption | bool | Defines if the logical volume of this storage class will be encrypted or not. | true | false |
| distr_ndcs | int | Defines the number of data chunks for the erasure coding scheme. | true | 1 |
| distr_npcs | int | Defines the number of parity chunks for the erasure coding scheme. | true | 1 |
| replicate | bool | Defines if the logical volume of this storage class will be replicated or not. | true | false |
| lvol_priority_class | int | Defines the priority class of a logical volume of this storage class. | true | 0 |
| max_namespace_per_subsys | int | Defines the number of namespaces per NVMe subsystem. | true | 1 |
| tune2fs_reserved_blocks | int | Defines the number of reserved blocks for tune2fs operations. | true | 0 |
Expand Down
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