Compare · Storage
Ceph vs ZFS:which should you choose?
Two open-source storage choices for Proxmox and private clouds: a distributed, self-healing cluster filesystem versus the rock-solid single-node filesystem with replication.
| Ceph | ZFS | |
|---|---|---|
| Architecture | Distributed object store (RADOS) with RBD block, CephFS and S3 gateway; data spread across nodes. | Local pooled filesystem with checksums, snapshots, compression; replication to another node is asynchronous (zfs send). |
| Minimum sensible size | 3 nodes (5+ recommended), 10/25 GbE, several OSDs per node. | 1 node; HA via replication + manual/scripted failover, or shared storage separately. |
| Performance | Scales with nodes; latency higher than local disks; needs NVMe and good network. | Excellent local performance, ARC caching; limited by one box. |
| Resilience | Survives node loss transparently; self-heals. | Survives disk loss; node loss means failover from a replica (minutes, possible data lag). |
| Operations | Needs understanding (PGs, CRUSH, rebalancing). | Simple; well-known tooling. |
| Best fit | HA clusters, scale-out capacity, S3 for apps. | Small clusters, single powerful hosts, backup targets, edge sites. |
Choose Ceph if…
- You run 3+ nodes and need true HA with live migration
- Capacity must grow by adding nodes
- You want S3-compatible object storage on-prem
Choose ZFS if…
- You have 1–2 nodes or an edge site
- Latency-sensitive databases on local NVMe
- Simplicity and predictable performance matter most
Our verdict
What we tell clients
Under ~3 nodes, ZFS with replication is faster, simpler and cheaper. From 3–5 nodes upward with 25 GbE and NVMe, Ceph delivers the HA and scale-out that make a private cloud feel like a cloud. Many estates use both: Ceph for the VM pool, ZFS on the PBS backup server.
Written by engineers who run both in production. No vendor paid for this page.
FAQ
Questions we get on calls
Can I run Ceph on 3 nodes?
Yes, with size=3/min_size=2 pools; performance is modest — budget NVMe OSDs and a dedicated 10/25 GbE cluster network.
Is ZFS HA possible?
Via replication (zfs send every few minutes) plus Proxmox HA; expect a small data lag on failover. True shared HA needs Ceph, SAN or NFS.
What about SAN?
FC/iSCSI SANs remain valid for enterprises that own them; Proxmox supports LVM over iSCSI and FC.
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