To achieve fault-tolerance for storage subsystem, duplication or even triplication of all the critical components is used. In converged
deployment scenario, StarWind runs virtual storage on multiple hypervisor nodes. In non-converged scenario, storage runs on many dedicated commodity
servers. The shared Logical Unit is basically “mirrored” between the hosts, maintaining data integrity and continuous operation even if one or more nodes fail. Every active host acts as a storage controller and every Logical Unit has duplicated or triplicated data back-end.
Multi-Path nature makes sure that even if some I/O fail, the work will just continue instantly with zero downtime. This way 99.99% uptime is achieved with 2-way replica and 99.9999% with 3-way replica. Going beyond triplication is considered pointless for most cases, unless it’s a life-critical system, like a nuclear power plant reactor control or cruise missile guidance operations.