SUMMARY: moving root; rebuilding the kernel

From: Brian O'Connor <boc_at_ironbark.bendigo.latrobe.edu.au>
Date: Tue, 11 Feb 1997 09:45:27 +1100 (EST)

Sorry for the slow summary;

              ===========Original Question============

   I am about to move the root and usr partition from a
SWXCR raid array to a single rz28. I searched the archives and
downloaded the INFOSHARE article

eg
http://www.service.digital.com:80/pubs/infoshare/arch/INFOSHARE-Summer95.Z
(BTW I had alot of trouble printing this out, just what kind of
postscipt do they use?)

In a nutshell it said;

--------------------------------------------------------------------------
assumed disk layout;
/ on a
swap on b
/usr on g

assume rz2 is the new disk
assume rz0 is the old disk

MAKEDEV rz2
disklabel -r -w rz2 rz28(assume rz28s)

newfs /dev/rrz2a rz28
newfs /dev/rrz2g rz28

fsck /dev/rrz2a
mount /dev/rz2a /mnt

dump 0f - / | (cd /mnt; restore xf -)

edit the /mnt/etc/fstab file
(replace rz0 with rz2)
eg
vi /mnt/etc/fstab
:%s/rz0/rz2/g

if swapdefault exists remove it and re-create it
to point at the new swap partition

umount /mnt
fsck /dev/rrz2a

fsck /dev/rrz2g
mount /dev/rrz2g /mnt

dump 0f - /usr | (cd /mnt; restore xf -)
umount /mnt
fsck /dev/rrz2g

shutdown and boot to the new disk
eg
>>>show dev
dka0.0.0.0.0 DKA0 RZ28
dka0.0.0.1.0 DKB0 RZ28
dka0.0.0.2.0 DKC0 RZ26

etc

if the new disk is
dka0.0.0.1.0 DKB0 RZ28
then

>>> init
>>> boot DKB0

You may need to clear the boot_osflags variable

>>> set boot_osflags ""

and set the auto_action to halt

>>> set auto_action halt
 
and set the bus_probe_algorithm to new

>>> set bus_probe_algorithm new
--------------------------------------------------------------------------


Some posts on this matter talk of rebuilding the kernel

eg

changing
config vmunix swap generic

to

config vmunix root on XXX swap on XXX dumps on XXX

(where XXX are partitions)

The INFOSHARE article does not mention this(a MAJOR oversight if
correct)

So! I have two questions

1. If I'm moving from "config vmunix swap generic" on a re0 device to
   "config vmunix swap generic" on a rz0 device do I need to rebuild the
kernel

2. If the boot_osflags console variable is cleared, and I just type "boot" will
  the system find rz0a(and hopefully boot from it) before looking at re0a

              ===========END Original Question============

responses;

>From fxjwk_at_aurora.alaska.edu Tue Feb 4 10:41:55 1997
Subject: Re: moving root; rebuilding the kernel

I believe "boot" without any device will look at bootdef_dev (or is it
boot_def_dev?) Anyway, it's the default device for boot, as opposed to
boot_dev, which is the last device booted from!
jo


>From alan_at_nabeth.cxo.dec.com Tue Feb 4 10:08:02 1997
Subject: Re: moving root; rebuilding the kernel

        The wonderful thing about "swap generic" is that the kernel
        doesn't need to know what the boot device is. It knows
        where the root file system is from the boot device provided
        by the console. You don't need to rebuild the kernel.

        I think that without boot_osflags, the system will boot
        to single user. The boot device is either provided with
        the boot command or comes from bootdef_dev.

>From andreww_at_adacel.com.au Tue Feb 4 10:07:06 1997
Subject: Re: moving root; rebuilding the kernel

Hi Brian,

> So! I have two questions
>
> 1. If I'm moving from "config vmunix swap generic" on a re0 device
> to "config vmunix swap generic" on a rz0 device do I need to
> rebuild the kernel

You need to rebuild the kernel to add the extra disk (rz0) into the
definition. If you are removing the re0a device then you may wish to
rebuild the kernel. Appart from that I don't see why you would need
to rebuild the kernel.

> 2. If the boot_osflags console variable is cleared, and I just type
> "boot" will the system find rz0a(and hopefully boot from it) before
> looking at re0a.

>>> set bootdef_dev DKA0

(or whatever ">>> show dev" returns for rz0)

Hope this helps.

-- 
Thankyou,
Andrew Weston
(Network Adminstrator)
>From m.luchini_at_ic.ac.uk  Tue Feb  4 22:08:42 1997
Subject: Re: moving root; rebuilding the kernel
Hi,
> 1. If I'm moving from "config  vmunix  swap  generic" on a re0 device to 
>    "config  vmunix  swap  generic" on a rz0 device do I need to rebuild the kernel
No need.  Generic means just that - ie look for a swap on the same
device as where the kernel is.
> 2. If the boot_osflags console variable is cleared, and I just type "boot" will
>    the system find rz0a(and hopefully boot from it) before looking at re0a 
No.  I think you need to change the bootdef_dev flag to point to the new
device.  The boot_osflags should not change - that determines whether
you want to boot to single user or multi user.
Ciao,							Marco
-------------------------------------------------------------------------
Marco Luchini                               Internet : m.luchini_at_ic.ac.uk
Department of Mathematics                   Telephone: +44 171 594 8551
Imperial College                                  Fax: +44 171 594 8517
London SW7 2BZ, UK                             
-------------------------------------------------------------------------
thanks to all who replied.
boc
-- 
------------------------------------------------------------
        Brian O'Connor, Unix Systems Consultant
              Latrobe University,Bendigo
          boc_at_ironbark.bendigo.latrobe.edu.au
------------------------------------------------------------
Received on Mon Feb 10 1997 - 23:58:50 NZDT

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