I have an enhanced stretch cluster configuration based on 2 IO's 2145 CG8. I want to swap out the CG8 with an SV1 node. Do you think I can add the new nodes as IO groups 3/4, then migrate the volume? Will I need a new license or can I migrate the license from CG8?

Hi Fernando - You could do as you propose, however, there is probably an easier way.  You can essentially take one of your CG8 nodes off line, change the WWN on the new SV1 to match the old CG8 and then plug in the SV1.  The hosts see a node go away and then come back (they think the new SV1 is the old CG8 coming back online).  After you check all paths, repeat for the other node in the IOGroup.  Here are the details of the procedure.

https://www.ibm.com/support/knowledgecenter/en/STPVGU_7.7.1/com.ibm.storage.svc.console.771.doc/svc_replacingnode_sv1_nondisrup.html

Also, your licenses are not tied to a SVC node so they will transfer. 

Hi Fernando,

We have replaced multiple SVC-CG8 nodes with DH8 nodes without any problems using the replace one-by-one procedure. The new node takes all characteristics of the old node so replacement should not be a problem.

Just follow the mentioned procedure and all should go well.