Please consider moving this question as-is (no need to recreate) to the proper forum for maximum visibility.  Questions written to the users' own "Discussions" space don't get the same amount of attention and can go unanswered for a long time.  You can do so by selecting "Move" under ACTIONS along the upper-right.  Then search for and select: "VNX Support Forum".  VNX Support Forum   You can review the steps in the following post (refer also to the referenced KB article itself for any possible updates that might have been made since it was posted to ECN):  How to rename the Control Station hostname in a dual CS configuration?
Hello All  Could someone help me in changing the hostname for my NS-120 and VNX-5300?  Currently, hostname is emcnas_i0 [root[NAME] ~]#  Existing /etc/hosts has 192.168.47.251  emcnas_i0   emcnas_i0  Tried adding 2 different combinations and rebooted. No affect.  192.168.47.251  test    emcnas_i0 192.168.47.251  test    test  BR// RG
Changing hostname of NS-120 & VNX-5300