Storage¶

The cluster uses a layered storage architecture to match workload requirements with the right storage backend. Distributed block storage, node-local volumes, and NAS-backed NFS mounts each serve a distinct purpose.

Architecture¶

flowchart TD
    Apps[Applications] -->|PersistentVolumeClaim| SC{StorageClass}

    SC -->|ceph-block| RC[(Rook Ceph\n3x 512GB NVMe\nReplicated Block)]
    SC -->|openebs-hostpath| OE[(OpenEBS\nLocal PV\nNode-Local Disk)]
    SC -->|nfs| SYN[(Synology NAS\n4-Bay 8TB\nNFS Shares)]

    RC -->|CephBlockPool| OSD1[worker-01\nNVMe OSD]
    RC -->|CephBlockPool| OSD2[worker-02\nNVMe OSD]
    RC -->|CephBlockPool| OSD3[worker-03\nNVMe OSD]

    subgraph Backup
        VS[VolSync] -->|Replicate PVCs| SYN
        SNAP[Snapshot Controller] -->|CSI Snapshots| RC
    end

Storage Classes¶

StorageClass	Provider	Replicated	Use Case
`ceph-block`	Rook Ceph	Yes (3x)	General-purpose workloads requiring high availability
`openebs-hostpath`	OpenEBS	No	Databases and workloads needing low-latency local disk
NFS (manual)	Synology NAS	RAID	Bulk media storage, shared datasets, backup targets

When to Use Each¶

Choosing a StorageClass

Rook Ceph -- Default choice for most workloads. Data is replicated across three NVMe drives on separate nodes, surviving single-node failures. Use for application databases, config volumes, and anything that needs to survive rescheduling.
OpenEBS -- Best for workloads that manage their own replication (e.g., PostgreSQL with CloudNativePG, etcd) or need the lowest possible latency. Data lives on a single node and is not replicated by the storage layer.
Synology NFS -- Ideal for large media libraries, bulk file storage, and backup destinations. Mounted via NFS from the 4-bay Synology NAS with 8 TB of usable storage.

Components¶

Component	Namespace	Purpose
Rook Ceph	`rook-ceph`	Distributed block storage on NVMe drives
OpenEBS	`openebs`	Local PV provisioner for node-local storage
VolSync	`system`	PVC backup and replication
Snapshot Controller	`system`	CSI volume snapshots

Sections¶

Page	Description
Rook Ceph	Distributed Ceph cluster on NVMe -- operator, cluster config, storage classes
OpenEBS	Local PV provisioner for node-local volumes
Backup & Restore	VolSync replication, CSI snapshots, Synology backup targets, restore procedures