I've managed to find the document I need ( vnx_p_replace_1u_sps.pdf ) on mydocuments.emc.com I was hampered by network connectivity issues and used my mobile to get it.  In short, replacing a faulty SPS in a two SPS system is non-disruptive and easy to do.  Our process was: The SPS powered up and the diagnostic LEDs did their thing. The green light flashed for a while ( self test? ) and is now solid and the array is no longer faulted.  I'm pleased to say that users were unaffected.
Hi,  I've got a VNX5100 with two SPs and two SPSs and one of the SPSs has failed.  The array is continuing to operate as normal and the write cache is enabled.  Can anyone confirm if the SPS replacement is non-disruptive and if there is a documented procedure for doing the replacement?  I've tried to find a procedure on SoLVe but there does not seem to be anything for SPSs.  My understanding of the SP and PSU design is that the PSUs are connected to the SPSs (one PSU per SPS) and power a common power bus in the DPE enclosure from which the SPs and drives draw power. This allows both for non-disruptive PSU replacement and I think non-disruptive SPS replacement. I'd like this confirmed before doing the actual replacement.  We are assuming/hoping but want confirmation that we can do the following: Can anyone confirm this?
VNX SPS replacement - is it non-disruptive?