To ensure successful virtual machine live migration, Oracle VM Manager requires the processor family and model number of the source and destination computer to be the same. A server processor compatibility group is a group of Oracle VM Servers with compatible processors, where a running virtual machine on one Oracle VM Server can safely be migrated and continue to run on another Oracle VM Server. Although Oracle VM Manager contains rules for server processor compatibility, you can create custom compatibility groups to ensure the ability to do smooth migrations is possible if you are certain that applications running within a virtual machine can survive the migration in the case where the family and model of a processor are not the same. If live migration is attempted between incompatible processors, an error message is displayed and the migration fails. Therefore you should be absolutely certain that migrations can be fully supported between all of the servers that belong to a custom server processor compatibility group.
All Oracle VM Servers are added to a default server processor compatibility group as they are discovered. A default server processor compatibility group is created when an Oracle VM Server is discovered if that Oracle VM Server has a processor that is new and unique to Oracle VM Manager. This happens automatically to ensure that live migration and high availability functions can be performed safely and without errors. You should never remove or edit the default server processor compatibility groups directly.
Each server processor compatibility group may include Oracle VM Servers that are members of one or more server pools. An Oracle VM Server may be included in multiple server processor compatibility groups. You can create server processor compatibility groups and select which Oracle VM Servers to include according to your needs. There is no limit to the number of server processor compatibility groups you may have. It is important to understand that when you create a server processor compatibility group, you are defining which servers can take part in live migration and other high availability functions. If you create a server processor compatibility group that contains servers with incompatible processors, live migration and many other functions may fail within your environment. Therefore, you should only create server processor compatibility groups if you are confident that live migration can take place across all of the servers within the group.
Since server processor compatibility groups are used to define which servers may be used for successful virtual machine live migration, it is worth reiterating that live migration is only supported between servers with matching release numbers. If you have an environment where there are mixed server versions, these servers should not be in the same compatibility group unless you are in the process of upgrading all of your servers to the same release.
More information on configuring server processor compatibility groups is available in Server Processor Compatibility Perspective in the Oracle VM Manager User's Guide.