Data redundancy

Virtuozzo Hybrid Infrastructure protects every piece of data by making it redundant. It means that copies of each piece of data are stored across different failure domains, to ensure that the data is available even if some of the failure domains are inaccessible.

Virtuozzo Hybrid Infrastructure automatically maintains a required number of copies within the cluster and ensures that all the copies are up to date. If a storage node becomes inaccessible when the host failure domain is used, copies from this node are replaced by new ones that are distributed among healthy storage nodes. If a storage node becomes accessible again after downtime, the out-of-date copies on it are updated.

The redundancy is achieved by one of two methods: replication or erasure coding. The chosen method affects the size of one piece of data and the number of its copies that will be maintained in the cluster. In general, replication offers better performance, while erasure coding leaves more storage space available for data (refer to Redundancy modes).