Persistent storageClass for GitLab on Kubernetes [closed]

Question

Using the official helm chart and documentation, I want to deploy GitLab to Kubernetes. The storage guide shows how to store persistent data and also offers example Helm values. Sadly this doesn't work for all services bundled in GitLabs chart. I want to set local-path as storage class but some pvcs ignore this:

$ kg pvc
NAME                        STATUS    VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
gitlab-minio                Pending                                      local-path     61s
gitlab-postgresql           Pending                                      local-path     61s
gitlab-prometheus-server    Pending                                                     61s
gitlab-redis                Pending                                      local-path     61s
repo-data-gitlab-gitaly-0   Pending                                                     19h

You can see that Prometheus and Gitaly doesn't have a storage class, algouth I set it in the values:

global:
  gitlabVersion: 11.0.1
  hosts:
    domain: gitlab.example.com
    https: true

  gitlab:
    https: true

  minio:
    enabled: true

  prometheus:
    enabled: false

  ingress:
    enabled: true
    tls:
      enabled: true
      secretName: gitlab-tls
    configureCertmanager: false
    annotations:
      certmanager.k8s.io/cluster-issuer: "letsencrypt-prod"

  certmanager:
    install: false

gitlab:
  gitaly:
    persistence:
      storageClass: local-path
      size: 50Gi

minio:
  persistence:
    enabled: true
    storageClass: local-path
    size: 20Gi
    accessMode: ReadWriteOnce

postgresql:
  persistence:
    enabled: true
    storageClass: local-path
    size: 10Gi

redis:
  persistence:
    enabled: true
    storageClass: local-path
    size: 5Gi

It also confuses me that some values need to be set under the global key, where others have their own key. But my primary question is: Why is my storageClass ignored for gitaly, altough I followed the example from the docs? And how can I configure the pvc of Prometheus, which isn't even part of this example?