upgrading 5.4 -> 6.0 without reinstalling. safe ?

[Robert Watson]

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.

Robert N M Watson