beatzaplenty
a854412117
Covers node 1 hardware/network layout, LVM-thin -> ZFS migration path, Ceph as the future HA storage upgrade, and baseline SSH/firewall hardening.
2.9 KiB
Node 1 Hardware Layout
Build node 1 so nodes 2/3 are drop-in identical later — don't re-architect disks or network when the cluster grows.
Disks — three separate roles, physically separate devices
- Boot/OS pool (
rpool) — 2x small SSDs (240-480GB plenty), ZFS mirror. Proxmox itself only. Never share with Ceph OSDs or bulk ZFS data pools. - Future Ceph OSD disks — must end up as raw, unformatted devices — no ZFS/RAID/LVM underneath (Ceph does its own replication; anything underneath just doubles copy-on-write/checksumming and hurts performance). Use enterprise SATA/NVMe SSDs with power-loss protection (PLP) — matters far more for Ceph write latency than for general ZFS use. Ceph needs 3 nodes minimum to go live, so on node 1 these disks either sit idle or run as a temporary local ZFS pool to be wiped and handed to Ceph once nodes 2/3 exist.
- Local ZFS "replicated tier" disks — separate set of disks (mirror or small raidz) for VMs kept on local storage + PVE replication rather than Ceph (latency-sensitive or non-critical workloads). This pool is permanent, not a placeholder.
If budget only allows one extra disk set right now: prioritize the future-Ceph disks, run everything on ZFS locally until nodes 2/3 arrive, then split workloads out. Avoid consumer QLC SSDs for either role — Ceph punishes it on latency, ZFS on sync writes/scrub.
Networking — cable and provision for the final topology now
Logically separate networks (ideally separate NICs/VLANs):
- Management — web UI / SSH
- Corosync — cluster quorum traffic, low-latency, unshared
- Ceph public — VM-to-OSD traffic
- Ceph cluster/backend — OSD-to-OSD replication (heaviest load)
Practical layout: 2x 10/25GbE bonded or split — one pair for Ceph, one for mgmt + corosync + VM traffic, with corosync on its own VLAN even if sharing a physical NIC. Get switch/cabling right on node 1 so nodes 2/3 are identical drops.
CPU / RAM sizing
Size for the end state, not day one — RAM is the hardest thing to retrofit. Budget covers:
- OS + ZFS ARC (ZFS wants RAM, not just disk)
- Ceph OSD daemons — realistically 3-5GB per OSD once running
- Actual VM workloads
Roughly a core per OSD on top of what VMs need. If OSDs won't be active for a while, that's headway, but buy for 3 nodes' worth of eventual OSD load.
Backup target (PBS)
Keep it off the Ceph/compute nodes if possible — its failure domain should be independent of the cluster. Modest separate machine or NAS: ZFS mirror or raidz2, ECC RAM if possible, capacity for retention policy. If it has to run as a VM inside the cluster short-term, that's a known compromise, not the end state.
Node 1 install sequence
- Install Proxmox VE fresh onto the ZFS boot mirror.
- Create the local ZFS "tier 2" pool for VM disks.
- Leave Ceph-earmarked disks idle, or provision as a temporary ZFS pool (to be wiped once Ceph goes live at 3 nodes).