docs: add info about storage

Author: spwoodcock

docs/tutorial/postgres.md

@@ -0,0 +1,45 @@
+# Kubernetes Storage
+
+Kubernetes doesn't provide storage - you need an external system.
+
+## Options
+
+### Local/HostPath
+
+- Data stored directly on node disk.
+- Fast but not portable, no redundancy.
+- Use only for caching, logs, ephemeral data.
+
+### Longhorn
+
+- Simple replicated storage across nodes.
+- Lightweight, but not very performant in prod.
+- Easy setup, good for homelabs and small clusters.
+
+### Cloud Volumes (AWS EBS, GCP PD, Azure Disk)
+
+- Fully managed by cloud provider.
+- Extremely reliable, zero ops overhead.
+- Trade-off: vendor lock-in and cost.
+
+### Ceph / Rook
+
+- Powerful distributed storage with full control.
+- Complex to operate - needs a lot of compute available.
+- Rock-solid, but only for large on-prem deployments with expertise.
+
+### NFS
+
+- Simple shared storage.
+- Easy setup, universal compatibility.
+- Performance depends on NFS server.
+- Fine for shared files, avoid for databases.
+- Probably also only good for a homelab mostly.
+
+## Quick Guide
+
+- **Homelab** --> Longhorn
+- **Production** --> Cloud volumes
+- **Large on-prem** --> Ceph (if you have the expertise)
+- **Testing/cache** --> Local volumes
+- **Shared files** --> NFS

docs/tutorial/storage.md

@@ -67,6 +67,7 @@ nav:
       - Storage: tutorial/storage.md
       - Certs & DNS: tutorial/certs-and-dns.md
       - GitOps With ArgoCD: tutorial/gitops-argocd.md
+      - Managing Databases: tutorial/postgres.md
   - Developer Guide:
       - Practices:
           - Dev Practices: https://docs.hotosm.org/dev-practices