Gentoo Archives: gentoo-dev

From: Christian HOFFMANN <hoffmann@××××.fr>
To: gentoo-dev@g.o
Subject: Re: [gentoo-dev] Further observations on moving root
Date: Wed, 20 Mar 2002 13:14:15
Message-Id: 3C98ECAC.5126.337C5B@localhost
In Reply to: Re: [gentoo-dev] Further observations on moving root by Martin Schlemmer
1 Hello,
2
3 I recently moved my root partition from one disk to the other and
4 experienced the same problem with /dev.
5
6 My solution is actualy simple, i did a mount /dev/hda3 /mnt/gentoo
7 (hda3 being my old root partition) and moved the hard drive content
8 with a tar cf | tar xfp from /mnt/gentoo to the new root. Working that
9 way, I copied the actual hard drive file not the dynamic filesystems in
10 /dev and /proc.
11
12 I worked without any problem, I'm also using this trick to backup my
13 system in a way similar of what is described in D.Robbins tutorial on
14 devlopperworks.
15
16 Regards
17
18 > On Wed, 2002-03-20 at 06:15, Fuper wrote:
19 > > If you ever might add a new disk drive and want to move the Gentoo
20 > > root partition onto the new (maybe faster) drive then my struggles
21 > > in doing that may be relevant to you. Copying the partition didn't
22 > > just work --- I found that the /dev directory initialization was not
23 > > obvious.
24 > >
25 > > I did conclude to my own satisfaction that the /sbin/rc script (v. 1.16)
26 > > is in error at line 312 and should read as follows:
27 > > 309 #we want devfsd running after a change of runlevel (if we return
28 > > 310 #from runlevel 'single')
29 > > 311 if [ -z "$(ps -A | grep devfsd)" ] && \
30 > > 312 [ -n "$(cat /proc/mounts | grep -e '/dev devfs')" ]
31 > > 313 then
32 > > 314 /sbin/devfsd /dev &>/dev/null
33 > > 315 fi
34 > > The distributed script had "cat mounts" and failed when devfsd
35 > > was not already running.
36 > >
37 > > After reading the devfs FAQ and Robbins paper on devfs at
38 > > IBM:developerWorks I concluded that a cleanly built root
39 > > partition should have an empty /dev directory. It is entirely
40 > > populated by devfs when that is "mounted" and accessed.
41 > >
42 > > BUT Gentoo linux, installed from build rc6 r14, crashes when
43 > > booted from the same /boot partition but using a new root ("/")
44 > > and an empty /dev (it had more interesting problems when
45 > > I attempted to create a fully populated dev/ by copying the
46 > > in-use /dev from the old root partition onto the new partition
47 > > s.a.
48 > > star -c /dev | star -x -C /mnt/partition # Don't do this
49 > >
50 > > I had to add the devfs mount option to the kernel so that
51 > > the grub commands that had been
52 > > root (hd0,0)
53 > > kernel /boot/bzImage root=/dev/hda2 hdc=ide-scsi
54 > > became now
55 > > root (hd0,0)
56 > > kernel /boot/bzImage root=/dev/sdb1 hdc=ide-scsi devfs=mount
57 > >
58 > > It is a mystery to me why it now becomes necessary to add
59 > > the devfs=mount option to the grub kernel command, booting
60 > > the same kernel using the same devfs.conf file and same
61 > > root partition (but copied onto a new disk). If this is obvious
62 > > to everyone else, then so be it; but maybe it is worth
63 > > documenting that under some conditions it becomes
64 > > necessary to add the kernel option.
65 > >
66 >
67 > This is because /sbin/init needs /dev/initctl, and as we dropped
68 > the initwrapper that created that if not existing, it fails when
69 > a unmounted /dev do not contain it.
70 >
71 > > I hope that this is helpful.
72 > > _______________________________________________
73 > > gentoo-dev mailing list
74 > > gentoo-dev@g.o
75 > > http://lists.gentoo.org/mailman/listinfo/gentoo-dev
76 > --
77 >
78 > Martin Schlemmer
79 > Gentoo Linux Developer, Desktop Team Developer
80 > Cape Town, South Africa
81 >
82 >
83 > _______________________________________________
84 > gentoo-dev mailing list
85 > gentoo-dev@g.o
86 > http://lists.gentoo.org/mailman/listinfo/gentoo-dev
87 >
88
89 -------------------------------------------
90 Christian HOFFMANN <hoffmann@××××.fr>