High availability (HA) keeps Virtuozzo Hybrid Infrastructure services operational even if the node they are located on fails. In such cases, services from a failed node are relocated to healthy nodes, according to the Raft consensus algorithm. High availability is ensured by:
Metadata redundancy. For a storage cluster to function, not all but just the majority of metadata servers must be up. By setting up multiple metadata servers in the cluster, you will make sure that if an metadata server fails, other metadata servers will continue controlling the cluster.
The required number of metadata servers is deployed automatically, based on recommended hardware configurations.
- Data redundancy. Copies of each piece of data are stored across different storage nodes, to ensure that the data is available even if some of the storage nodes are inaccessible. For more information, refer to Data redundancy.
- Monitoring of node health.