From Lars Appel:

You could use SYSGEN to create two different config groups in the SYS account, one for the old system (e.g. CONFOLD), and one for the new system (e.g. CONFNEW).

To create the new config you start with one of the existing config templates, e.g. CONF9x8.SYS for 3000/9x8 systems. Use BASEGROUP to open it, adjust IO to your needs and KEEP it as CONFNEW.

Just make sure that every disk gets an LDEV in the new config. Paths and LDEVs (except for LDEV 1) do not need to be the same on the new system. MPE/iX will notice (and "collect") all available volumes during bootup (as long as they are "visible" by a configured LDEV number).

Shutdown the system, plug the disks into the new box, power it on, boot from the primary path (or enter the appropriate path for LDEV 1) and at the ISL prompt do a START NORECOVERY [NOSYSSTART] GROUP=CONFNEW.

You may also need to adjust NMCONFIG with NMMGR as a different system may have the LAN cards at a different physical path. In case you make a copy of NMCONFIG, make sure it stays on LDEV 1 (FILE;DEV=1).