One question that comes up frequently is whether you can mix Solaris 10 and Solaris 11 in different logical domains under Oracle VM Server for SPARC. The answer is yes depending only on the system software requirements for the underlying hardware platform.

Different versions of Solaris 10 and 11 can exist side-by-side on the same server and can act as control, service, I/O or guest domains subject only to the minimum software levels documented in the System Requirements section of the Oracle VM Server for SPARC Release Notes.

Here's an example just taken from a running system. First, here's the control domain, which is running Solaris 10. I've highlighted a guest running Solaris 11.

# uname -a
SunOS atl-sewr-24 5.10 Generic_147440-01 sun4v sparc SUNW,SPARC-Enterprise-T5220
# ldm -V

Logical Domains Manager (v 2.1)
        Hypervisor control protocol v 1.7
        Using Hypervisor MD v 1.3

System PROM:
        Hypervisor      v. 1.10.0       @(#)Hypervisor 1.10.0 2011/04/27 16:19\015

# ldm list
NAME             STATE      FLAGS   CONS    VCPU  MEMORY   UTIL  UPTIME
primary          active     -n-cv-  SP      16    4G       1.6%  120d 17h 
atl-sewr-pool-148 active     -n----  5001    8     2G       0.1%  119d 21h 
atl-sewr-pool-152 active     -n----  5000    8     4G       0.2%  112d 19h
atl-sewr-pool-154 active     -n----  5002    8     2G       0.1%  120d 15h 
atl-sewr-pool-155 active     -n----  5003    16    2G       0.0%  26d 14h 30m

This system is running Oracle VM Server 2.1 with a Solaris 10 control domain. Hmm, I should update this machine to 2.2 when I get a few free moments. Upgrading is very straightforward. Here's a display logging into the highlighted guest:

Last login: Mon May 21 10:18:16 2012 from dhcp-adc-twvpn-
Oracle Corporation      SunOS 5.11      11.0    November 2011
sewr@atl-sewr-pool-152:~$ uname -a
SunOS atl-sewr-pool-152 5.11 11.0 sun4v sparc SUNW,SPARC-Enterprise-T5220
sewr@atl-sewr-pool-152:~$ cat /etc/release
                          Oracle Solaris 11 11/11 SPARC
  Copyright (c) 1983, 2011, Oracle and/or its affiliates.  All rights reserved.
                            Assembled 18 October 2011

sewr@atl-sewr-pool-152:~$ sudo virtinfo -ct
Password: 
Domain role: LDoms guest
Control domain: atl-sewr-24
sewr@atl-sewr-pool-152:~$ 

That's running the GA version of Solaris 11, so I probably should update that some time too. Note the use of the virtinfo -ct command that lets the guest get information about the hosting environment.

Summary

You can mix and match versions of Solaris in logical domains. All the different combinations work: Solaris 10 and/or Solaris 11 control and service domains with Solaris 10 and/or Solaris 11 guests. Mixing different guest OS levels on the same server is one of the traditional reasons for using virtual machines in the first place since virtual machines were invented some 40 years ago, used to run production and test systems in parallel while upgrading OS levels. This can easily be done with Oracle VM Server for SPARC (Logical Domains).