Peter Tribble wrote: > On 11/8/06, *Sarah Jelinek* <Sarah.Jelinek at sun.com > <mailto:Sarah.Jelinek at sun.com>> wrote: > > Margot Miller wrote: > > Hey Sarah, > > > > I have a few questions regarding not supporting > > "in place" upgrades. > > > > Do most other O/S'es offer "in place" upgrade? > > > Well.. Fedora Core 5 does. I believe Ubuntu does. I don't know > about MacOS. > > The issue with in place upgrades is that: > 1. It makes the system unusable for that period of time that the > upgrade > is running. > 2. There is no rollback mechanism, short of a full restore, if > something > gets broken. > > Our choice to use live upgrade means these things are no longer > issues. > The one thing it does mean however, is that extra disk space is > needed > for the alternate boot environment that is created to enable live > upgrade. > > > I believe "in-place" upgrades are essential, and removing them is a > colossal mistake. > > In fact, I expect in-place upgrades to be the most common upgrade path > for many years. Space may be cheaper than it was in the past, but it's > certainly not free. Besides, scrapping in-place upgrades means > abandoning most of the installed base (including, I suspect, all machines > using pre-installed configurations). > > I don't actually see why Live Upgrade is necessarily easier than an > in-place upgrade. At least with a normal in-place upgrade you're > booted off the new version in a known state, rather than an old > version of Solaris in an unknown state. Actually, this may not be the case. If upgrade fails for some reason you may not be able to boot your system. With live upgrade you can boot back always to the last known good running version of Solaris. It provides a fallback mechanism.
Also, even if upgrade succeeds, with development ongoing in OpenSolaris there may be a bug that causes a panic on boot that just keeps on going. This makes the system unusable as well if you can't even get to the failsafe mode. Live upgrade at least allows you to get the system back up and running. sarah **** > > Going further, why isn't it possible to do an upgrade via some sort > of patch mechanism? > > The argument that disks are now so large that it's no longer > necessary to worry about space simply isn't true. Systems with > 18G drives (or similar) are still commonplace and entirely viable. > With the growth in virtualization, large drives will get chopped up > into much smaller chunks for allocation to installed systems. > And many Sun systems still get shipped with 73G drives. While > this may seem excessive now, it's not going to look generous > in 5 years time. Besides, Sun still sell reconditioned systems with > 9G drives, and we mustn't completely ignore the hobbyist market > where less generous configuarrions are common. > > -- > -Peter Tribble > http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/
