FAQ: PCA Mixed version nodes in same track and Live Migration of VMs in an X4, X5 or X6 Mixed PCA Rack

Asset ID:	1-71-2130104.1
Update Date:	2017-05-04
Keywords:

Solution Type Technical Instruction Sure

Solution 2130104.1 : FAQ: PCA Mixed version nodes in same track and Live Migration of VMs in an X4, X5 or X6 Mixed PCA Rack

Applies to:

Oracle Virtual Compute Appliance X4-2 Hardware - Version All Versions and later
Information in this document applies to any platform.

Goal

Can we have mixed versions of compute nodes in same PCA rack? i.e. X4,X5 or X6 nodes in same PCA rack.
Do we need to create a separate group/pool for the new version nodes when the rack is upgraded with the higher version compute nodes ? example adding X6-2 nodes in a PCA rack consisting of x5 nodes.

Are there any known issues with VM Live Migration of VM's in PCA rack with mixed X4 & X5 or X6 Servers . i.e. Migrating vm's from X4 to X5 or X6 servers and vice versa.

Solution

PCA 2.2.1 version and above is required for using x6-2 nodes in the rack. One can either use the same Group/Pool as the x5-2 nodes or can create new tenant groups which is new feature added as part of 2.2.1 for the new x6-2 nodes.

when you mix x5 and x6 nodes, the VMs may not be able to migrate among different versions , though they should be fine migrating in the same node versions.

The default behavior is that VMs can only be live migrated between identical servers, so live migration would not be permitted by default between X4 and X5 servers. But the administrator can enable migration between different server types by setting up Server Processor Compatibility Groups as documented at http://docs.oracle.com/cd/E35328_01/E35332/html/vmusg-svrpool-cpu-comp.html .

When this is done, VMs can be live migrated between the different servers in the group. it is generally safe to migrate from "older to newer servers" in the same product family (in this case X4 to X5) as the newer servers will have all the processor features of the older one, and possibly more. It is not generally safe to migrate from "new to old", as the OS or applications in the VM may detect a processor feature on the newer server and then try to use it after being migrated to the older.

It will work if there are no new processor features (in this case on the X5, which is unlikely) that are detected when the VM is running there that the guest VM tries to use, but don't exist on the older server (in this case X4).

The same should apply to any PCA with mixed servers in the rack.

Attachments

This solution has no attachment