How can I monitor persistent volume usage of containers separately?

[kmpartner]

I have followed tutorial "Deploying WordPress using Dynamic NFS Provisioner"
wordpress was deployed and started to monitor pvc usage using prometheus.

query in prometheus using
kubelet_volume_stats_used_bytes
kubelet_volume_stats_capacity_bytes
seems to display total of deployed node.

How can I extract pvc usage of wordpress and usage of mariaDb separately?
I am not familar with monitoring and prometheus. Are there any way to display disk usage of containers and pvc?