upgrading 5.4 -> 6.0 without reinstalling. safe ?

[Jan Grant]

On Thu, 10 Nov 2005, Robert Watson wrote:

> 
> On Wed, 9 Nov 2005, Ronald Klop wrote:
> 
> 
> > > PS.: Just did an upgrade remote from 5.4-RELEASE to 6.0-RELEASE without
> > > any problems. Steps taken as described above ;)
> > 
> > How do you reboot into single-usermode from remote? (Rebooting isn't really
> > the problem, working in single-usermode is.)
> 
> Typically, using a serial console which allows you to specify the boot flags
> and access the console remotely.  A serial console is an invaluable tool for
> remote administration in the event of upgrades, hardware failures, etc,
> especially if your box supports remote bios and raid management using a serial
> port but not a command line tool.
> 
> It is possible to do upgrades without single user mode, but it comes with
> risks -- if you do this, you want to make sure that you've shut down any
> important services, and blocked logins by users.  Otherwise applications may
> keel over as shared objects are replaced (generally, pluggable ones),
> configuration files change, programs start and stop working for windows as
> they are replaced, etc.  This is not a recommended approach, and I don't
> promise it will work, but I've done remote upgrades on multiuser but quiesced
> systems many, many times without problems.

FWIW I've just done a successful remote source-based upgrade from 5.4 to 
6.0 (I'm brave) with no problems. I use a second root and /usr to be 
able to run mergemaster, etc, on a spare copy whilst preserving the 
"live" system, then nextboot to boot the second drive. Providing you 
remember to rebuild or disable any 5.x-era kernel modules from ports 
(nvidia, rtc, etc) prior to the reboot it should work fine and offers a 
simple backout in the case of disaster. On a multiuser system this 
obviously works better if you arrange your setup to work in a "read-only 
root/usr" setup, so late-in-the-day changes by users to stuff under /etc 
aren't lost.


-- 
jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44 (0)117 3317661   http://ioctl.org/jan/
Goedel would be proud - I'm both inconsistent _and_ incomplete.