My storage server, the ML110 G5 has been running OpenSolaris 2008.11. With the release of OpenSolaris 2009.06, I wanted to upgrade and wondered if I should have left a spare slice of disk so I could perform a live upgrade. With the rest of the network dependent on this server for services (DNS, iSCSI LUNs, file and print serving), a failed upgrade didn't appeal.
It turns out that the the upgrade was very easy and a spare slice was not required:
Step one: Upgrade the Package Manager:
$ pfexec pkg install SUNWipkg
Step two: Run the Package Manager and select "Update All".
Wait while the new package requirements are evaluated, downloaded and installed.
Step three: Reboot
That's it. Checking /etc/release now reports:
OpenSolaris 2009.06 snv_111b X86
Copyright 2009 Sun Microsystems, Inc. All Rights Reserved.
Use is subject to license terms.
Assembled 07 May 2009
Although I'm not an expert in IPS, the OpenSolaris packaging system, my understanding is that the previous version of the operating system is still on the system in the form of a ZFS snapshot, so if I have any problems, I should be able to rollback without too many problems.
Compared with upgrading other operating systems, OpenSolaris has been an absolute dream. Highly recommended.