Appendix C. Upgrading from RHEV-H 3.6 to RHVH 4.2 While Preserving Local Storage
Environments with local storage cannot migrate virtual machines to a host in another cluster (for example when upgrading to version 4.2) because the local storage is not shared with other storage domains. To upgrade RHEV-H 3.6 hosts that have a local storage domain, reinstall the host while preserving the local storage, create a new local storage domain in the 4.2 environment, and import the previous local storage into the new domain. Follow the procedure in Upgrading to RHVH While Preserving Local Storage in the Red Hat Virtualization 4.0 Upgrade Guide, but install a RHVH 4.2 host instead of a 4.0 host.
An exclamation mark icon appears next to the name of the virtual machine if a MAC address conflict is detected when importing the virtual machines into the 4.2 storage domain. Move the cursor over the icon to view a tooltip displaying the type of error that occurred.
Select the Reassign Bad MACs check box to reassign new MAC addresses to all problematic virtual machines. See Importing Virtual Machines from Imported Data Storage Domains in the Administration Guide for more information.