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Version: 3.1

Create PX-Fast PVCs

PX-Fast is a Portworx feature that enables an accelerated IO path for the volumes that meet certain prerequisites. It is optimized for workloads requiring consistent low latencies. PX-Fast is built on top of a Portworx PX-StoreV2 datastore.

note
  • PX-Fast requires a special license for the functionality to be active. Contact Portworx support team for obtaining this license.

  • PX-Fast works only if Portworx is installed with PX-StoreV2 datastore.

Prerequisites

You must have deployed Portworx with PX-StoreV2 datastore.

Create PX-Fast PVCs

Perform the following steps to create PX-Fast volumes.

Create a StorageClass

  1. Save the following as a YAML file:

    kind: StorageClass
    apiVersion: storage.k8s.io/v1
    metadata:
    name: px-fast
    provisioner: kubernetes.io/portworx-volume
    parameters:
    repl: "1"
    fastpath: "true"
    allowVolumeExpansion: true

    Note that this StorageClass will have 1 replica, and the Portworx volumes referring to this StorageClass will also have 1 replica.

  2. Run the following kubectl apply command to create a StorageClass:

    kubectl apply -f <px-fast>.yaml
    storageclass.storage.k8s.io/px-fast created
  3. Verify that the StorageClass is created:

    kubectl describe storageclass px-fast
    Provisioner:           kubernetes.io/portworx-volume
    Parameters: fastpath=true,repl=1
    AllowVolumeExpansion: <unset>
    MountOptions: <none>
    ReclaimPolicy: Delete
    VolumeBindingMode: Immediate
    Events: <none>

Create a PVC

  1. Save the following as YAML file:

    kind: PersistentVolumeClaim
    apiVersion: v1
    metadata:
    name: px-fast-pvc
    spec:
    storageClassName: px-fast
    accessModes:
    - ReadWriteOnce
    resources:
    requests:
    storage: 1Gi
  2. Run the following kubectl apply command to create a PX-Fast PVC:

    kubectl apply -f <px-pvc>.yaml
  3. Verify that a persistent volume claim is created:

    kubectl get pvc

Deploy an application using a PX-Fast PVC

To utilize PX-Fast on the above PVCs, the application pods must run on the same node where the volume replica exists. The following sample deployment spec uses the stork.libopenstorage.org/preferLocalNodeOnly: "true" annotation, which enforces the pod to be scheduled on the node where the volume replica exists:

apiVersion: apps/v1
kind: Deployment
metadata:
name: mysql
spec:
selector:
matchLabels:
app: mysql
strategy:
rollingUpdate:
maxSurge: 1
maxUnavailable: 1
type: RollingUpdate
replicas: 1
template:
metadata:
annotations:
stork.libopenstorage.org/preferLocalNodeOnly: "true"
labels:
app: mysql
spec:
schedulerName: stork
containers:
- image: mysql:5.6
name: mysql
env:
- name: MYSQL_ROOT_PASSWORD
value: password
ports:
- containerPort: 3306
volumeMounts:
- name: mysql-persistent-storage
mountPath: /var/lib/mysql
volumes:
- name: mysql-persistent-storage
persistentVolumeClaim:
claimName: px-fast-pvc

Note that the schedulerNamefield in the above spec is set to stork. From Stork version 2.9.0 or newer, the schedulerName is set to stork by default.

The annotation stork.libopenstorage.org/preferLocalNodeOnly: "true" enforces the pod to be scheduled on the node where the volume replica exists. To avoid this enforced behavior, you can choose not to specify the stork.libopenstorage.org/preferLocalNodeOnly: true annotation. In such a case, Stork will do best-effort to place the application pod on the node where the replica exists, but if the application pod gets attached to a non-replica node, it cannot use PX-Fast.

note

PX-Fast is not supported for PVCs with more than 1 replica. It is also not supported on the aggregated volumes.

Reference

PX-Fast volumes using pxctl

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