You can install Open Enterprise Server (OES) 2015 SP1 as a VM host server for either the Xen or KVM virtualization services included with SLES 11. To understand why you might want your VM host server to have OES 2015 SP1 installed, see
Why Install OES Services on Your VM Host? in the OES 2015 SP1: Planning and Implementation Guide.
IMPORTANT:Only Xen supports NetWare 6.5 SP8 running as a VM guest server. KVM does not. Both Xen and KVM support OES 2015 SP1 running as a VM guest server.