Tip: Installing two instances of Solaris/OpenSolaris on one machine
By Roman Strobl on Oct 08, 2008
If you try to install two instances of Solaris/OpenSolaris on one machine, you'll get into trouble - the installer will want to install into the first primary Solaris partition on the disk. Clearly the installer doesn't support having multiple instances of Solaris/OpenSolaris on one computer. I learned recently a neat trick which can overcome the limitations of the installers. This way I can install both Solaris 10 and OpenSolaris on my machine in dualboot.
The trick is to install Solaris/OpenSolaris and after installation change the type of the partition where the OS got installed to something else (e.g. FAT32 or NTFS). Fdisk can do the job nicely or you can use other favorite partitioning tool to change the partition type. During second installation you will be able to create a new primary Solaris partition after the first partition and the installer will install without any issues because it won't be aware of the second instance of Solaris/OpenSolaris.
After the installation you can switch the first Solaris partition type back to Solaris and update your GRUB's menu.lst file and you have now a working dual boot with two instances of Solaris/OpenSolaris.