Moving Power Systems from an old HMC to a new HMC

Technote (FAQ)

Are there any steps that need to be performed on an old HMC before moving a server to a new HMC?

Answer

This technote is written for customers that use DHCP on their HMC's private network to connect to the Power servers. Before you physically remove your older Power5, Power6 or Power7 server connections from their existing HMC and move them to the new HMC you will need to first perform a logically remove so they will be ready to connect to a new HMC and get a DHCP lease.

If you just move the physical connections from one HMC to another without removing the logical connection first then the servers might not connect to the new HMC or take a long time doing so.

Performing a Logical Remove

To remove the connection you used the Connections task menu and the sub-menu item is

"Reset or remove connection". 

Take the remove option to remove the server connection from their existing HMC.
Navigation through the GUI would be through following task option menus

Systems Management
-> Servers
--> Select server
---> Expand Connections task menu
----> Click on Reset or remove connection
-----> Use the remove option and press OK to remove the system

The command line option to do a remove has following syntax
rmsysconn -o remove --ip <FSP IP address to remove>
You can see the IP addresses of the flexible service processor (FSP) for a managed system by running
lssysconn -r all
If you use the rmsysconn command instead of the HMC GUI then make sure you remove all IP addresses associated with the server.

Perform the physical connections to new HMC

After you logically remove a system from an existing HMC, physically move the cable over to the new HMC's private switch.

Perform command to prepare HMC for new connections
On the new HMC you might need to run following command.
mksysconn -o auto
It will take several minutes for the server to show up on the new HMC, and when it does it will be as an IP address in state Failed Authentication. You can use the update password task to authenticate the HMC with the server using the appropriate HMC access password for the server.