SFS Turbo is a shared file system with high availability and durability. It is suitable for applications that contain massive small files and require low latency, and high IOPS. This section describes how to use an existing SFS Turbo file system to statically create PVs and PVCs for data persistence and sharing in workloads.

Prerequisites

You have created a cluster and installed the CCE Container Storage (Everest) add-on in the cluster.
Before creating a cluster using commands, ensure kubectl is used to access the cluster. For details, see Connecting to a Cluster Using kubectl.
You have created an available SFS Turbo file system, and the SFS Turbo file system and the cluster are in the same VPC.

Constraints

Multiple PVs can use the same SFS or SFS Turbo file system with the following restrictions:
- Do not mount all PVCs/PVs that use the same underlying SFS or SFS Turbo file system to a pod. This leads to a pod startup failure because not all PVCs can be mounted to the pod due to the same volumeHandle values of these PVs.
- The persistentVolumeReclaimPolicy parameter in the PVs is suggested to be set to Retain. Otherwise, when a PV is deleted, the associated underlying volume may be deleted. In this case, other PVs associated with the underlying volume malfunction.
- When the underlying volume is repeatedly used, enable isolation and protection for ReadWriteMany at the application layer to prevent data overwriting and loss.

Using an Existing SFS Turbo File System on the Console

Statically create a PVC and PV.

Choose Storage in the navigation pane and click the PVCs tab. Click Create PVC in the upper right corner. In the dialog box displayed, configure the PVC parameters.

Parameter	Description
PVC Type	In this example, select SFS Turbo.
PVC Name	Enter the PVC name, which must be unique in the same namespace.
Creation Method	You can create a storage volume or use an existing storage volume to statically create a PVC based on whether a PV has been created. In this example, select Create new to create a PV and PVC at the same time on the console.
PV^a	Select an existing PV volume in the cluster. Create a PV in advance. For details, see "Creating a storage volume" in Related Operations. You do not need to specify this parameter in this example.
SFS Turbo^b	Click Select SFS Turbo. On the displayed page, select the SFS Turbo file system that meets your requirements and click OK.
PV Name^b	Enter the PV name, which must be unique in the same cluster.
Access Mode^b	SFS Turbo volumes support only ReadWriteMany, indicating that a storage volume can be mounted to multiple nodes in read/write mode. For details, see Volume Access Modes.
Reclaim Policy^b	Only Retain is available. This indicates that the PV is not deleted when the PVC is deleted. For details, see PV Reclaim Policy.
Mount Options^b	Enter the mounting parameter key-value pairs. For details, see Configuring SFS Turbo Mount Options.

a: The parameter is available when Creation Method is set to Use existing.

b: The parameter is available when Creation Method is set to Create new.

Click Create to create a PVC and a PV.
You can choose Storage in the navigation pane and view the created PVC and PV on the PVCs and PVs tab pages, respectively.

Create an application.

In the navigation pane on the left, click Workloads. In the right pane, click the Deployments tab.

Click Create Workload in the upper right corner. On the displayed page, click Data Storage in the Container Settings area and click Add Volume to select PVC.

Mount and use storage volumes, as shown in Table 1. For details about other parameters, see Workloads.

**Table 1** Mounting a storage volume
Parameter	Description
PVC	Select an existing SFS Turbo volume.
Mount Path	Enter a mount path, for example, /tmp. This parameter indicates the container path to which a data volume will be mounted. Do not mount the volume to a system directory such as / or /var/run. Otherwise, containers will be malfunctional. Mount the volume to an empty directory. If the directory is not empty, ensure that there are no files that affect container startup. Otherwise, the files will be replaced, causing container startup failures or workload creation failures. NOTICE: If a volume is mounted to a high-risk directory, use an account with minimum permissions to start the container. Otherwise, high-risk files on the host machine may be damaged.
Subpath	Enter the subpath of the storage volume and mount a path in the storage volume to the container. In this way, different folders of the same storage volume can be used in a single pod. tmp, for example, indicates that data in the mount path of the container is stored in the tmp folder of the storage volume. If this parameter is left blank, the root path is used by default.
Permission	Read-only: You can only read the data in the mounted volumes. Read/Write: You can modify the data volumes mounted to the path. Newly written data will not be migrated if the container is migrated, which may cause data loss.

In this example, the disk is mounted to the /data path of the container. The container data generated in this path is stored in the SFS Turbo file system.

After the configuration, click Create Workload.
After the workload is created, the data in the container mount directory will be persistently stored. Verify the storage by referring to Verifying Data Persistence and Sharing.

(kubectl) Using an Existing SFS File System

Use kubectl to access the cluster.

Create a PV.

Create the pv-sfsturbo.yaml file.

apiVersion: v1
kind: PersistentVolume
metadata:
  annotations:
    pv.kubernetes.io/provisioned-by: everest-csi-provisioner
  name: pv-sfsturbo    # PV name.
spec:
  accessModes:
  - ReadWriteMany      # Access mode. The value must be ReadWriteMany for SFS Turbo.
  capacity:
    storage: 500Gi       # SFS Turbo volume capacity.
  csi:
    driver: sfsturbo.csi.everest.io    # Dependent storage driver for the mounting.
    fsType: nfs
    volumeHandle: <your_volume_id>   # SFS Turbo volume ID.
    volumeAttributes:
      everest.io/share-export-location: <your_location>   # Shared path of the SFS Turbo volume.

      storage.kubernetes.io/csiProvisionerIdentity: everest-csi-provisioner
  persistentVolumeReclaimPolicy: Retain    # Reclaim policy.
  storageClassName: csi-sfsturbo          # Storage class name of the SFS Turbo file system.
  mountOptions: []                         # Mount options.

**Table 2** Key parameters
Parameter	Mandatory	Description
volumeHandle	Yes	SFS Turbo volume ID. How to obtain: Log in to the CCE console, choose Service List > Storage > Scalable File Service, and select SFS Turbo. In the list, click the name of the target SFS Turbo volume. On the details page, copy the content following ID.
everest.io/share-export-location	Yes	Shared path of the SFS Turbo volume. Log in to the CCE console, choose Service List > Storage > Scalable File Service, and select SFS Turbo. You can obtain the shared path of the file system from the Mount Address column.
mountOptions	No	Mount options. If not specified, the following configurations are used by default. For details, see Configuring SFS Turbo Mount Options. mountOptions: - vers=3 - timeo=600 - nolock - hard
persistentVolumeReclaimPolicy	Yes	A reclaim policy is supported when the cluster version is or later than 1.19.10 and the Everest version is or later than 1.2.9. Only the Retain reclaim policy is supported. For details, see PV Reclaim Policy. Retain: When a PVC is deleted, the PV and underlying storage resources are not deleted. Instead, you must manually delete these resources. After that, the PV is in the Released status and cannot be bound to the PVC again.
storage	Yes	Requested capacity in the PVC, in Gi.
storageClassName	Yes	The storage class name of SFS Turbo volumes is csi-sfsturbo.

Run the following command to create a PV:
```
kubectl apply -f pv-sfsturbo.yaml
```

Create a PVC.

Create the pvc-sfsturbo.yaml file.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-sfsturbo
  namespace: default
  annotations:
    volume.beta.kubernetes.io/storage-provisioner: everest-csi-provisioner

spec:
  accessModes:
  - ReadWriteMany                  # The value must be ReadWriteMany for SFS Turbo.
  resources:
    requests:
      storage: 500Gi               # SFS Turbo volume capacity.
  storageClassName: csi-sfsturbo       # Storage class of the SFS Turbo volume, which must be the same as that of the PV.
  volumeName: pv-sfsturbo    # PV name.

**Table 3** Key parameters
Parameter	Mandatory	Description
storage	Yes	Requested capacity in the PVC, in Gi. The value must be the same as the storage size of the existing PV.
storageClassName	Yes	Storage class name, which must be the same as the storage class of the PV in 1. The storage class name of SFS Turbo volumes is csi-sfsturbo.
volumeName	Yes	PV name, which must be the same as the PV name in 1.

Run the following command to create a PVC:
```
kubectl apply -f pvc-sfsturbo.yaml
```

Create an application.

Create a file named web-demo.yaml. In this example, the SFS Turbo volume is mounted to the /data path.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-demo
  namespace: default
spec:
  replicas: 2
  selector:
    matchLabels:
      app: web-demo
  template:
    metadata:
      labels:
        app: web-demo
    spec:
      containers:
      - name: container-1
        image: nginx:latest
        volumeMounts:
        - name: pvc-sfsturbo-volume    #Volume name, which must be the same as the volume name in the volumes field.
          mountPath: /data  # Location where the storage volume is mounted.
      imagePullSecrets:
        - name: default-secret
      volumes:
        - name: pvc-sfsturbo-volume    # Volume name, which can be customized.
          persistentVolumeClaim:
            claimName: pvc-sfsturbo    # Name of the created PVC.

Run the following command to create a workload to which the SFS Turbo volume is mounted:
```
kubectl apply -f web-demo.yaml
```
After the workload is created, you can try Verifying Data Persistence and Sharing.

Verifying Data Persistence and Sharing

View the deployed application and files.
1. Run the following command to view the created pod:
```
kubectl get pod | grep web-demo
```
  Expected output:
```
web-demo-846b489584-mjhm9   1/1     Running   0             46s
web-demo-846b489584-wvv5s   1/1     Running   0             46s
```
2. Run the following commands in sequence to view the files in the /data path of the pods:
```
kubectl exec web-demo-846b489584-mjhm9 -- ls /data
kubectl exec web-demo-846b489584-wvv5s -- ls /data
```
  If no result is returned for both pods, no file exists in the /data path.
Run the following command to create a file named static in the /data path:
```
kubectl exec web-demo-846b489584-mjhm9 --  touch /data/static
```
Run the following command to view the files in the /data path:
```
kubectl exec web-demo-846b489584-mjhm9 -- ls /data
```
Expected output:
```
static
```
Verify data persistence.
1. Run the following command to delete the pod named web-demo-846b489584-mjhm9:
```
kubectl delete pod web-demo-846b489584-mjhm9
```
  Expected output:
```
pod "web-demo-846b489584-mjhm9" deleted
```
  After the deletion, the Deployment controller automatically creates a replica.
2. Run the following command to view the created pod:
```
kubectl get pod | grep web-demo
```
  The expected output is as follows, in which web-demo-846b489584-d4d4j is the newly created pod:
```
web-demo-846b489584-d4d4j   1/1     Running   0             110s
web-demo-846b489584-wvv5s    1/1     Running   0             7m50s
```
3. Run the following command to check whether the files in the /data path of the new pod have been modified:
```
kubectl exec web-demo-846b489584-d4d4j -- ls /data
```
  Expected output:
```
static
```
  If the static file still exists, the data can be stored persistently.
Verify data sharing.
1. Run the following command to view the created pod:
```
kubectl get pod | grep web-demo
```
  Expected output:
```
web-demo-846b489584-d4d4j   1/1     Running   0             7m
web-demo-846b489584-wvv5s   1/1     Running   0             13m
```
2. Run the following command to create a file named share in the /data path of either pod: In this example, select the pod named web-demo-846b489584-d4d4j.
```
kubectl exec web-demo-846b489584-d4d4j --  touch /data/share
```
  Check the files in the /data path of the pod.
```
kubectl exec web-demo-846b489584-d4d4j -- ls /data
```
  Expected output:
```
share
static
```
3. Check whether the share file exists in the /data path of another pod (web-demo-846b489584-wvv5s) as well to verify data sharing.
```
kubectl exec web-demo-846b489584-wvv5s -- ls /data
```
  Expected output:
```
share
static
```
  After you create a file in the /data path of a pod, if the file is also created in the /data path of the other pod, the two pods share the same volume.

Related Operations

You can also perform the operations listed in Table 4.

**Table 4** Related operations
Operation	Description	Procedure
Creating a storage volume (PV)	Create a PV on the CCE console.	Choose Storage in the navigation pane and click the PVs tab. Click Create PersistentVolume in the upper right corner. In the dialog box displayed, configure parameters. Volume Type: Select SFS Turbo. SFS Turbo: Click Select SFS Turbo. On the page displayed, select the SFS Turbo volume that meets the requirements and click OK. PV Name: Enter the PV name, which must be unique in the same cluster. Access Mode: SFS volumes support only ReadWriteMany, indicating that a storage volume can be mounted to multiple nodes in read/write mode. For details, see Volume Access Modes. Reclaim Policy: Only Retain is supported. For details, see PV Reclaim Policy. Mount Options: Enter the mounting parameter key-value pairs. For details, see Configuring SFS Turbo Mount Options. Click Create.
Expanding the capacity of an SFS Turbo volume	Quickly expand the capacity of a mounted SFS Turbo volume on the CCE console.	Choose Storage in the navigation pane and click the PVCs tab. Click More in the Operation column of the target PVC and select Scale-out. Enter the capacity to be added and click OK.
Viewing events	You can view event names, event types, number of occurrences, Kubernetes events, first occurrence time, and last occurrence time of the PVC or PV.	Choose Storage in the navigation pane and click the PVCs or PVs tab. Click View Events in the Operation column of the target PVC or PV to view events generated within one hour (event data is retained for one hour).
Viewing a YAML file	You can view, copy, and download the YAML files of a PVC or PV.	Choose Storage in the navigation pane and click the PVCs or PVs tab. Click View YAML in the Operation column of the target PVC or PV to view or download the YAML.