Per the doc:  For a dual-SP system:    The software installation procedure reboots SP A, and then after the reboot of SP A completes, it reboots SP B. This causes any connected servers that are not configured for high availability (not connected to each SP) to lose  As long as your hosts are dual pathed and failover works, then you should have no issues. This is for installing the enabler. Adding the DAE itself after the software will not cause reboots and the array can be up and processing IO.  -Ryan
I am adding a DAE expansion unit to our live system.  Can I do this while the system is up?  Will adding the expansion software cause any problems that will make problems for systems using the SAN?
Adding DAE-AX to live system