Drop ZFS-replication as an interim HA step; jump straight to Ceph

Simplifies the storage model to one long-term tier (Ceph) instead of
two. Node 1 runs local ZFS only until nodes 2/3 join, at which point
Ceph goes live and VMs migrate onto it directly.

docs/00-overview.md

@@ -14,19 +14,16 @@ new hardware. Before reusing that workaround on the new box:
 
 ## End goal
 
-3-node Proxmox VE cluster with HA-managed VMs. Two ways to get VM disks
-available on more than one node (see `02-storage-zfs-ceph.md`):
+3-node Proxmox VE cluster with HA-managed VMs backed by **Ceph** — true
+distributed shared storage, sync replication, near-zero RPO on failover
+(see `02-storage-zfs-ceph.md`). Ceph needs 3+ nodes and a fast dedicated
+network, so it can't exist until nodes 2 and 3 are up.
 
-1. **Ceph** — true distributed shared storage, sync replication, needs 3+
-   nodes and a fast dedicated network. Zero/near-zero RPO on failover.
-2. **ZFS + storage replication** — local ZFS pool per node, Proxmox
-   replicates VM disks between nodes on a schedule (as often as every
-   minute). Lighter weight, async — failover loses whatever changed since
-   last replication.
-
-Starting point: ZFS + replication (lighter, works from node 1 onward).
-Ceph is the upgrade path once 3 nodes exist and/or zero-RPO failover
-matters enough to justify the overhead.
+Deliberately no intermediate "ZFS + storage replication" HA step. Node 1
+runs local ZFS for boot + VM storage with no cluster-wide HA until Ceph
+goes live — as soon as nodes 2/3 join, VMs move onto Ceph rather than
+adopting ZFS replication as a stopgap. Simpler end state, one storage
+model to operate instead of two.
 
 ## Cluster fundamentals (apply from node 1 onward)
 
@@ -44,14 +41,16 @@ matters enough to justify the overhead.
 ## Rollout sequence
 
 1. Build node 1 per `01-hardware-node1.md` — fresh PVE install on ZFS boot
-   mirror, local ZFS "tier 2" pool for VM disks, Ceph-earmarked disks left
-   idle or as a temporary ZFS pool.
+   mirror, Ceph-earmarked disks left idle (or as a temporary local ZFS
+   pool, to be wiped later — see `02-storage-zfs-ceph.md`).
 2. Migrate VMs off old hardware via `vzdump` → copy backups → `qmrestore`
-   onto the new ZFS storage (converts disks to ZVOLs).
+   onto the new ZFS storage (converts disks to ZVOLs). No HA yet — single
+   node.
 3. Apply hardening (`04-security-hardening.md`) and networking
    (`03-networking.md`) before exposing the node beyond the LAN.
 4. Add nodes 2 and 3 identically (same disk/network layout).
-5. Join cluster, stand up dedicated corosync network, configure
-   replication and HA groups.
-6. Optionally migrate the Ceph-earmarked disks from temporary ZFS to real
-   Ceph OSDs once 3 nodes are up.
+5. Join cluster, stand up dedicated corosync network.
+6. Wipe the Ceph-earmarked disks (if used as temporary ZFS) and
+   initialize Ceph across all 3 nodes.
+7. Migrate VMs from local ZFS onto Ceph-backed storage, then configure HA
+   groups.