I have had a very stable CX4-120 running about 1 year out of service. There is only one SPS which has faulted and the battery indicater lights up on the back. I have a replacement SPS ready, but I have doubts whether I need to power down the SPE in order to just change the SPS. Can I just turn the faulted SPS off - replace it - and turn on the new one with same cable setting? Can't find any documentation that addresses this specific situation. Has anyone experience in this or know what to do?
I believe you can, provided array is Up. Only CX4-120 in CX4 family has this exception which can run on singls SPS.
If the CX4-120 is running with write cache disabled it means that its taking power from PDU. So if you remove the SPS and replace it there shouldn't be any issue. However, it is recommended if you can do it during the downtime.
Below is the Cabling Diagram for your ready reference:
Thank you very much for your quick answer. The Cabling is exactly like the diagram, so I feel more confident now as I can also see write cache is disabled.