Longhorn is an open source software, originally designed by Rancher Labs, as distributed block storage system for Kubernetes.
Today, Longhorn is a CNCF project which delivers a cloud-native distributed storage platform for Kubernetes that can run anywhere.
1. Longhorn volumes can be used as persistent storage for distributed stateful applications in the kubernetes cluster.
Longhorn allows users to specify the size of volume, requirement of IOPS and number of synchronous replicas needed across the hosts which supply the storage resource for the volume. With these capabilities, users’ kubernetes resources are able to apply the PVC and corresponding PV for every Longhorn volume or longhorn storage class to create a PV for a workload automatically.
2. Block storage can be partitioned into longhorn volumes to use kubernetes volumes with or without a cloud provider.
Longhorn helps simplify the storage system through partitioning a large block storage controller into a number of smaller storage controllers.
3. Increases availability by replicating block storage across multiple nodes and data centers
4. Support external storage (NFS or AWS S3) to store back up data
5. Allows users to create cross-cluster disaster recovery to quickly recover data of a primary kubernetes cluster through backup in a secondary kubernetes cluster
6. Set up recurring schedule for snapshots of a volume or backups operations.
Users can set the frequency of recurring snapshots of backup to NFS or S2-compatible secondary storage at favourable period of time (hourly, daily, weekly, monthly and yearly) as well as the specific time and the number recurring snapshots and backup sets are kept and specific time.
7. Allows users to restore volumes from backup
8. Longhorn updates are enable without obstructing persistent volumes
