This exporter provides 3 metrics to monitoring block storage, hostpath and nfs pvcs.

1. pvc_usage: Provides the percentage of PVC usage.
2. pvc_mapping: Provides the mapping between pod and pvc.
3. pvc_used_MB: Provide the specific usage of PVC, the unit is MB.

If you want to monitor pvc usage and the native mertics are not available.

The following storage provisioners has been tested..
1.longgorn
2.trident
3.rook-ceph
4.aliyun flexvolume
5.iomesh
6.nutanix-csi
...

The following architectures:
1.X86_64
2.ARM64

helm repo add pvc-exporter https://kais271.github.io/pvc-exporter/helm3/charts/  
kubectl create namespace pvc-exporter  
helm install demo pvc-exporter/pvc-exporter --namespace pvc-exporter --version v0.1.4-beta  

#pvc_usage
The value is pvc usage percent that equal pvc_used_MB/pvc_requested_MB. Some informations about pvc is also provided.
pvc_usage{container="pvc-exporter", endpoint="metrics", grafana_key="pvc-957af729-41e3-40cc-b90d-71ffab0ec149-web-3", instance="10.3.179.59:8848", job="demo-pvc-exporter", namespace="pvc-exporter", persistentvolume="pvc-957af729-41e3-40cc-b90d-71ffab0ec149", persistentvolumeclaim="www-web-3", pod="demo-pvc-exporter-phbmt", pvc_namespace="default", pvc_requested_size_MB="1024.0", pvc_requested_size_human="1G", pvc_type="block", pvc_used_MB="2.5", service="demo-pvc-exporter"} 0.01

#pvc_mapping
This metrics provide mapping between pvc and pod.
pvc_mapping{container="pvc-exporter", endpoint="metrics", grafana_key="pvc-e555d811-c0b1-4e0b-b3ee-25c7cb1c66ee-web-0", host_ip="192.168.175.129", instance="10.3.179.59:8848", job="demo-pvc-exporter", mountedby="web-0", namespace="pvc-exporter", persistentvolume="pvc-e555d811-c0b1-4e0b-b3ee-25c7cb1c66ee", persistentvolumeclaim="www-web-0", pod="demo-pvc-exporter-phbmt", pod_namespace="default", service="demo-pvc-exporter"} 0

You can use this expression " sum without (grafana_key,container,pod,service,namespace,job,instance,endpoint,pvc_namespace,pvc_requested_size_MB) ( (pvc_usage) + on(grafana_key) group_left(persistentvolumeclaim,mountedby,pod_namespace)pvc_mapping*0) " to grafana to monitoring pvc usage.
note!!! You can see one pvc usage percent more than 1, that's a nfs pvc. As we know the nfs and hostpath pvc will exceed the requested size if the provisioner not support quota.
For dashboard, you can refer /docs/PVC-Dashboard.json