Defining Quality of Service

Simplyblock's CSI driver supports QoS (Quality of Service) limits on logical volumes.

To configure the QoS limits, simplyblock offers the following two options.

Option 1: StorageClass

Using StorageClass instances, you can define QoS limits for all volumes sharing the same StorageClass. This enables the definition of paid performance classes for the user.

With applying a StorageClass, the QoS limits are locked in at volume creation time.

StorageClass with QoS

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: qos-volumes
provisioner: csi.simplyblock.io
parameters:
  qos_rw_iops: 1000
  qos_rw_mbytes: 125
  qos_r_mbytes: 125
  qos_w_mbytes: 125
reclaimPolicy: Delete
volumeBindingMode: Immediate

Option 2: PVC Annotations

If more control is required, simplyblock supports defining QoS limits on a per-PVC basis using Kubernetes PVC annotations.

When using PVC annotations, no definition inside a StorageClass is required. If both are defined, PVC annotations take precedence.

Like with StorageClass definitions, the QoS limits are locked in at volume creation time.

PVC with QoS annotations

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: my-pvc
  annotations:
    simplybk/qos-rw-iops: "1000"
    simplybk/qos-rw-mbytes: "125"
    simplybk/qos-r-mbytes: "125"
    simplybk/qos-w-mbytes: "125"
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  storageClassName: simplyblock-csi-sc

QoS Parameters

All parameters are optional. Default is 0 (no limit).

StorageClass Parameter	Annotation	Description
qos_rw_iops	simplybk/qos-rw-iops	Max read+write IOPS
qos_rw_mbytes	simplybk/qos-rw-mbytes	Max read+write throughput (MB/s)
qos_r_mbytes	simplybk/qos-r-mbytes	Max read throughput (MB/s)
qos_w_mbytes	simplybk/qos-w-mbytes	Max write throughput (MB/s)

Note

Annotation values override StorageClass values per parameter. You must only use annotations for values you want to override.