Dell EMC PowerVault MD3400 and MD3420 Series Storage Arrays Deployment Guide

Non-redundant configurations are configurations that provide only a single data path from a host to the storage array. This type of configuration is only recommended for noncritical data storage. Path failure from a failed or removed cable, or a failed or removed RAID controller module results in loss of host access to storage on the storage array.

Redundancy is established by installing separate data paths between the host and the storage array. Each data path is connected to one of the two RAID controller modules installed in the storage array. Redundancy protects the host from losing access to data if there is a path failure, because both RAID controller modules can access all the disks in the storage array.