Huawei OceanStor Dorado supports Non-disruptive Upgrade (NDU), which allows the storage system’s software (firmware) to be upgraded while services are running. In a traditional storage environment, an upgrade might require a system reboot or cause a failover that interrupts I/O for several seconds or minutes. However, Dorado's NDU leverages the multi-controller architecture and advanced caching mechanisms.

During an NDU, the system upgrades controllers one by one or in batches. While one controller is being upgraded and rebooted, its workloads are transparently taken over by other active controllers in the same cluster. Because the host-side multipathing software handles the path failover and the storage system maintains cache mirroring, the application servers experience zero downtime and negligible performance impact. This feature is essential for mission-critical environments that require 24/7 availability and cannot afford scheduled maintenance windows for routine software updates.