Quantity of servers

One of the strongest features of Virtuozzo Hybrid Infrastructure is scalability. The bigger the cluster, the better Virtuozzo Hybrid Infrastructure performs.

To achieve the best performance, keep at least 20 percent of the cluster capacity free.

One server (no VM redundancy)

Even though three nodes are recommended even for the minimum configuration, you can start evaluating Virtuozzo Hybrid Infrastructure with just one node and add more nodes later. In this case, you may need to provide data redundancy by using the disk failure domain, not the host failure domain as in a multi-node cluster.

At the very least, a storage cluster must have one metadata service and one chunk service running. However, such a configuration will have two key limitations:

• Just one MDS will be a single point of failure. If it fails, the entire cluster will stop working.
• Just one CS will be able to store just one chunk replica. If it fails, the data will be lost.

In a single-node installation, it is not possible to restart virtual machines by using VM high availability.

Two servers (no VM redundancy)

In terms of redundancy, a two-node cluster is the same as a single-node cluster. High availability for virtual machines is not supported in this case.

Three servers (minimum for high availability)

Three servers are required to test all of the product features, and this is the minimum number for a production environment.

The minimum configuration ensures that the cluster can survive the failure of one node without data loss. The minimum cluster configuration must have at least three metadata services running. SSD/NVMe disks can be assigned the system, metadata, and cache roles at the same time, freeing up more disks for the storage role.

Five and more servers (recommended for high availability and optimal TCO)

At least five nodes are required to ensure that the cluster can survive failure of two nodes without data loss. For improved resilience, performance, and fault tolerance it is recommended to create production clusters from at least ten nodes.

The recommended cluster configuration must have five metadata services running.