Dell POWERVAULT MD3620I - Manual (Page 20)

This example shows a fully redundant fabric configuration. If a fibre channel switch or HBA fails, the alternate switch
still connects both storage controllers in the storage array. If a storage controller also fails, the host can still access the
remaining controller and all virtual disks fail over to that controller. A complete loss of access to storage occurs if any
other element fails.
Figure 9. Configuration Showing Single-Point Failure
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