[CentOS] Old hd, new machine

Robert Heller heller at deepsoft.com
Wed Dec 16 16:33:10 UTC 2009

At Wed, 16 Dec 2009 09:55:49 -0600 CentOS mailing list <centos at centos.org> wrote:

> Robert Heller wrote:
> > At Wed, 16 Dec 2009 07:33:38 -0600 CentOS mailing list <centos at centos.org> wrote:
> > 
> >> Jussi Hirvi wrote:
> >>>>> What should I do to make an existing CentOS (5.4) disc boot up on a new
> >>>>> computer?
> >>>>> [...]
> >>>>> Would it be enough to boot with a DVD in rescue mode, or boot with
> >>>>> another hd, and install grub?
> >>> On 16.12.2009 12:16, Sorin Srbu wrote:
> >>>> For me it has worked to just install the old hd in the new machine and boot
> >>>> it up. Kudzo takes care of the rest.
> >>> Then you have been lucky. :-) For me, the startup stopped already before 
> >>> the CentOS splash screen. I guess something was wrong with the initrd.
> >>>
> >> If the disk holding the / partition needs a different driver than what you had 
> >> during the install, you have to rebuild the initrd.  Anaconda knows how to do 
> >> that, kudzo can't.  You can do it from a rescue-mode boot, but you may have to 
> >> know the right module names.
> > 
> > *Before* swapping out the old disk, add an appropriate scsi_hostadapterN
> > (N >= 1) alias to /etc/modprobe.conf and then do:
> > 
> > mkinitrd -f /boot/initrd-`uname -r`.img `uname -r`
> > 
> > All should be good then.
> > 
> > IF both the old machine and the new machine have your basic, vanila IDE
> > disks, then there is no problem.
> I've always wished the install/rescue disk had a mode to do this for you 
> after you've moved the disks or restored a backup.  The reason you are 
> trying to bring up the new machine may be that the old one is dead - and 
> anaconda knows a lot more about picking the right driver modules than I 
> ever will.  I've done it a time or two by installing a system on the new 
> (or matching) hardware with a separate /boot partition, then making sure 
> the old/new systems are updated to the same versions and keeping the new 
> /boot but copying the rest of the old system over.

Until very recently, I've moved disks from one AHA-29xxx SCSI system to
another AHA-29xxx SCSI system.  Same driver, different controller
card...  My latest move was on the same system, different disks: SCSI
disks (AHA-29160N controller) to SATA (ahci flavored controller).  In
this case, the motherboard, etc. were working just fine (so where one
of the *old* SCSI disks -- it died a couple of weeks later).  The
AHA-29160N controller card is still in the machine, with nothing
connected to it (one never knows if some interesting piece of
hardware happens along).

As for proper module: you just need to pay close attention to what
anaconda is doing as it loads drivers.  At least that is what I've seen.
(I *always* use text mode with install/rescue disks.)


Robert Heller             -- 978-544-6933
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