Virtuoso Cluster supports optional fault tolerance by storing partitions in more than one copy if desired. This is a cluster-only feature, providing for transparent fail-over with fully transactional semantics. This feature is in no way related to the other forms of replication discussed in the Virtuoso documentation. This feature can be used for load balancing of read-intensive workloads and for fault tolerance of arbitrary workloads in a tightly coupled cluster. This feature is not suited for synchronizing geographically distributed copies.

Fault tolerance is enabled at the level of logical cluster. Making the logical cluster __ALL fault tolerant has the effect of making all the normally non fault tolerant database objects into fault tolerant ones.