DRBD & LINSTOR: high availability without a full Ceph cluster
DRBD (Distributed Replicated Block Device) is an open-source Linux kernel module that mirrors a block device between two or more servers in real time — every write is synchronously replicated, so if one node goes down, the other already has an identical, up-to-date copy. LINSTOR is LINBIT’s open-source orchestration layer on top of DRBD, managing volumes, snapshots, and failover across a cluster rather than by hand.
Why this matters for a storage server
Ceph is the right tool for scale-out clusters — many nodes, self-healing, built for growth. But not every deployment needs that much cluster: a two-node high-availability pair, common in edge sites, small offices, or budget-constrained deployments, is a different shape of problem. DRBD/LINSTOR solve HA at that smaller scale without the operational overhead of running a full Ceph cluster for just two boxes.
How 45Drives uses it
45Drives has a direct partnership with LINBIT, the company behind DRBD and LINSTOR, to bring synchronous block-level replication and cluster orchestration to 45Drives’ ZFS-based storage servers — positioned as a complementary high-availability option alongside Ceph, not a replacement for it. Where Ceph is the answer for distributed, many-node scale, DRBD/LINSTOR is the answer for “I need two servers to fail over to each other reliably.”
Why that matters if you’re evaluating storage
- Right-sized HA. Not every deployment needs Ceph’s operational complexity — DRBD gives you real synchronous replication for a two-node pair without standing up a cluster.
- Open source, not a proprietary SAN feature. Like everything else in this stack, DRBD/LINSTOR are auditable, community-supported projects, not a black-box vendor add-on.
- A genuine partnership, not just a bundled dependency. 45Drives and LINBIT worked together directly on this integration, rather than 45Drives simply packaging an unmodified upstream project.
Learn more
- linbit.com — LINBIT, the company behind DRBD and LINSTOR
- DRBD documentation
- LINSTOR documentation
See Ceph and ZFS for the other two storage foundations this stack is built on, depending on the scale of the deployment.