Longhorn¶

Cloud-native distributed block storage for Kubernetes — CNCF Incubating, lightweight, Kubernetes-native.

Overview¶

Longhorn is a lightweight, Kubernetes-native distributed block storage system by SUSE/Rancher. It provides per-volume replicated storage using a microservices architecture where each volume gets its own dedicated storage controller. It integrates via CSI, supports incremental snapshots and S3 backups, and is the simplest distributed storage to deploy on K8s.

Key Facts¶

Attribute	Detail
Repository	github.com/longhorn/longhorn
Stars	~6k+ ⭐
Latest Version	v1.11.1 (April 2026)
Language	Go, C++ (engine)
License	Apache 2.0
Governance	CNCF Incubating
Company	SUSE / Rancher

Evaluation¶

Pros	Cons
Simplest K8s distributed storage	Not suitable for large-scale (100+ node) clusters
Per-volume engine — fine-grained control	Performance lower than Ceph for heavy workloads
Incremental snapshots + S3 backups	V2 Data Engine (SPDK) still in tech preview
Non-disruptive upgrades	No object or file storage (block only)
Intuitive dashboard UI	Each volume runs its own engine process
CNCF Incubating, active community
Disaster recovery built-in

Architecture¶

flowchart TB
    subgraph K8sCluster["Kubernetes Cluster"]
        subgraph Node1["Node 1"]
            LM1["Longhorn Manager\n(DaemonSet)"]
            E1["Engine\n(volume controller)"]
            R1["Replica 1"]
        end
        subgraph Node2["Node 2"]
            LM2["Longhorn Manager"]
            R2["Replica 2"]
        end
        subgraph Node3["Node 3"]
            LM3["Longhorn Manager"]
            R3["Replica 3"]
        end
        CSI["CSI Driver"]
    end

    Pod["Pod + PVC"] --> CSI --> E1
    E1 -->|"sync replicate"| R1
    E1 -->|"sync replicate"| R2
    E1 -->|"sync replicate"| R3

    style K8sCluster fill:#2e7d32,color:#fff

Key Features¶

Feature	Detail
Synchronous replication	2–3 replicas across nodes
Incremental snapshots	Point-in-time recovery
Automated backups	To S3 or NFS
Disaster recovery	Standby volumes in remote cluster
Non-disruptive upgrades	Upgrade without volume disconnection
V2 Data Engine	SPDK-based for high-performance (tech preview)
Parallel replica rebuild	v1.11: faster recovery