Persistent volumes allows to manage the storage in a central manner. This way you can specify volume configuration in a separate file and do not have to specify per each pod.
This way an administrator or yourself can create volumes for you, and you can use them creating Persistent volume claim.
A persistent volume should specify the access mode and the storage capacity.
But things get complicated when the cluster is composed with more than one node as nodes don’t share the same storage. For this case, let the cluster administrator set up a storage solution and use Persistent volumes with Persistent volume claim.
A user can create a persistent volume claim to use a previously created Persistent volumes. A claim should include the access mode and a storage capacity to request.