Making HDD-Backed Proxmox Ceph Clusters Fast — NVMe Metadata, One Optane Per Spindle, and What It Costs You
Flash pricing has made all-NVMe hard to justify, and enterprise HDDs are worth another look. Getting acceptable latency out of them on hyper-converged Proxmox Ceph means moving RocksDB off the spindle, pairing each disk with its own Optane through bcache — Optane specifically, because NAND endurance is wrong for that job — and being honest about the failure modes it buys you.