Paul Humphreys rambles on....

One of the barriers to getting customers to upgrade to a new version of software is usually the time it takes, the risks of the process and of course application support. I remember many years ago upgrading servers in the middle of the night with half inch tapes and later on cdroms whirring as the upgrade ran. The backups one had to take beforehand. Thankfully things are better now but I want to evangelise some technology that takes a lot of the pain away from upgrading.

Sun calls the software Live Upgrade. For non technical folks it basically means you perform the upgrade while the system is still doing the job that you bought it to do without interruption to the service. Once you are happy with the upgrade process result you then reboot your server and you are then running the upgraded system. The main win for this is that if for some reason you have to return to the old version you just reboot off the old disk. Live Upgrade handles these Boot environments with handy aliases so you can remember what to boot from to get what version. Older versions did not support mirrored boot disks but these are now supported.

You don't need to be upgrading Solaris to take advantage of Live Upgrade. You can install packages, patches using it and then bring them into production when you are ready. It takes the risk out of these processes and enables a fall back recovery process for free. If you manage Solaris systems I strongly suggest you take a look at it today.

Comments:

too bad most systems have only two disk slots. split the mirror to live upgrade the second drive. you are now exposed. if the primary drive - the one you are running off of - should fail, you are toast.

Posted by MikeTLive on October 19, 2006 at 12:13 AM PDT #

Actually that is not true, well it is true about the disk slots but not always true about the exposure.

You can use other partitions for live upgrade so in this age of very large disks you can have a 2 10Gb partitions on each disk and use them for Live upgrade. This is exactly what I have done on my home server, which I upgrade every two weeks to the next Solaris Express build.

Now if you have not preplanned this then that makes life hard but adding a third disk temporarily while you move data around solves this. You can even use an external USB drive for this.

When we get to be able to have full support for ZFS root file systems all this kefuffle will go away as everything will just live in one pool. You either have enough space or you don't (and since you can then compress the root file system you don't need so much space), but that is in the future.

Posted by Chris Gerhard on October 19, 2006 at 12:45 AM PDT #