Re: backward compatibility: how far can it reasonably go?

[Brad Spencer <brad%anduin.eldar.org@localhost>]

"Greg A. Woods" <woods%planix.ca@localhost> writes:

> At Tue, 7 Dec 2021 20:37:26 -0800 (PST), Paul Goyette <paul%whooppee.com@localhost> wrote:
> Subject: Re: backward compatibility: how far can it reasonably go?
>>
>> Without looking at the details of your backtrace, the issue with
>> ifconfig(8) could be related to PRs kern/54150 and/or kern/54151.
>
> Aw, damn, my memory is too short!  Thanks for reminding me of those!
>
> The kernel crash was IPF-related, and in my test back then I was testing
> on an i386 machine, which at the time did not, IIRC (and we know what
> that might mean), was not running IPF.
>
> Anyway, the two machines I'm upgrading do need to run IPF, at least
> until they are running a new OS with new pkgs.
>
> I'm beginning to think the only way to avoid that rabbit hole in order
> to get these upgrades done in the next week will be to shut them down
> and do the upgrades by mounting their filesystems in their dom0s.
>
> --
> 					Greg A. Woods <gwoods%acm.org@localhost>
>
> Kelowna, BC     +1 250 762-7675           RoboHack <woods%robohack.ca@localhost>
> Planix, Inc. <woods%planix.com@localhost>     Avoncote Farms <woods%avoncote.ca@localhost>


You can also shut the DOMU down and present the disks to another DOMU in
real time using "xl block-attach ...."  just use the "r" device if you
use devices or the file otherwise.  I have done this for many years with
PV DOMUs on many different Xen versions.  Once you have the disks
presented, mostly I just "tar -xpf ...." the sets or my own build of
userland on top of the old system.  Use postinstall after that usually
once the system is booted up again with the newer kernel and newer
userland.  You will need the etc sets for postinstall, but nothing has
been scary there.

Although I have never seen this problem, there may be trouble if the
block size that the DOMU sees of the disks is different from what DOM0
sees.  There have been comments about this from time to time.

I have also done other variations of this using a copy of /rescue/tar to
extract the new userland onto a live DOMU system usually from the Xen
console in single user mode.  This has also generally worked out just
fine and I use that in the case where I have made /usr a LVM disk inside
of the DOMU and it is a pain to present that to another DOMU.





-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org