Mailinglist Archive: opensuse (2008 mails)

["David C. Rankin" <drankinatty@xxxxxxxxxxxxxxxxxx>]

Rajko M. wrote:
> On Friday 24 April 2009 04:40:36 pm Greg Freemyer wrote:
>
> > Yes but at least the first stage of booting is typically handled by
> > grub, and I don't remember seeing a solution to keeping the grub disk
> > designations stable as drives come and go.
> >
> > Curious if anyone else has?
>
> You mean (hd0) pointing to different device?
>
> # cat /boot/grub/device.map
> (fd0)   /dev/fd0
> (hd1)   /dev/disk/by-id/ata-WDC_<...1>
> (hd0)   /dev/disk/by-id/ata-WDC_<...2>
>
> I don't see problem. 
>
> The /boot/grub/menu.lst has 
> /dev/disk/by-id/ata-WDC_<...1> and 
> /dev/disk/by-id/ata-WDC_<...2> 
> entries. 
>
> If it would be label used syntax is different, but still it seems that it 
> works fine. It could that openSUSE grub is patched to allow this kind of 
> naming. 

Rajko,

        Has a point. Normally it isn't a problem with just two disks, but when 
you get
into sets of raid arrays it is a must. (/boot/grub/device.map) For the past
couple of years things seemed relatively stable with drives not swapping order
under the new labeling schemes, but something must be coming unglued, because
in the past several months I count at least three separate threads about this,
Linda's included. The device.map file helps by providing the mapping between
the fake drive names/labels that are now used and the old hardware hd(1,2,3..)
convention.

        In Linda's case it can be used to tell the boot process which device is 
hd0
and which is hd1 so they don't get swapped and lead to grub trying to boot from
/dev/sda3 on what was in reality Linda's /dev/hdb. I ran into this problem  and
it drove me nuts when I had 2 device mapper containing 2 different md arrays
that drove grub nuts. If you are experiencing a similar problem, then look at
your devices in /dev/mapper and/or with df -h to figure out what devices are 
what:

[21:48 archangel:/srv/www] # l /dev/mapper
total 0
drwxr-xr-x  2 root root       0 2009-04-24 04:49 .
drwxr-xr-x 23 root root       0 2009-04-24 04:49 ..
crw-rw----  1 root root  10, 60 2009-04-24 04:49 control
brw-------  1 root disk 254,  1 2009-04-24 04:49 nvidia_fdaacfde
brw-------  1 root disk 254,  6 2009-04-24 04:49 nvidia_fdaacfde5
brw-------  1 root disk 254,  7 2009-04-24 04:49 nvidia_fdaacfde6
brw-------  1 root disk 254,  8 2009-04-24 04:49 nvidia_fdaacfde7
brw-------  1 root disk 254,  9 2009-04-24 04:49 nvidia_fdaacfde8
brw-------  1 root disk 254,  0 2009-04-24 04:49 nvidia_fffadgic
brw-------  1 root disk 254,  2 2009-04-24 04:49 nvidia_fffadgic5
brw-------  1 root disk 254,  3 2009-04-24 04:49 nvidia_fffadgic6
brw-------  1 root disk 254,  4 2009-04-24 04:49 nvidia_fffadgic7
brw-------  1 root disk 254,  5 2009-04-24 04:49 nvidia_fffadgic8

        Your drives will be the names *without* a number.

[23:07 archangel:/srv/www] # df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/nvidia_fffadgic5
                       19G  9.5G  8.0G  55% /
none                  2.0G     0  2.0G   0% /dev/shm
/dev/mapper/nvidia_fffadgic6
                      114M   16M   93M  15% /boot
/dev/mapper/nvidia_fffadgic7
                       37G  346M   35G   1% /home
/dev/mapper/nvidia_fdaacfde7
                       20G   17G  2.0G  90% /mnt/ecs
/dev/mapper/nvidia_fdaacfde5
                       69M   19M   47M  29% /mnt/ecs/boot
/dev/mapper/nvidia_fdaacfde8
                      437G  141G  275G  34% /mnt/ecs/home

        Then just create and/or edit your /boot/grub/device.map to map your 
drives to
the real hardware naming scheme. Here, if I want the drive
/dev/mapper/nvidia_fdaacfde to boot as hd0, I just do the following:

[21:01 archangel:/srv/www] # cat /boot/grub/device.map
(hd0) /dev/mapper/nvidia_fdaacfde
(hd1) /dev/mapper/nvidia_fffadgic
(fd0) /dev/fd0

        Take a look at what you have Linda, and see if it makes sense, then 
post back.

-- 
David C. Rankin, J.D.,P.E.
Rankin Law Firm, PLLC
510 Ochiltree Street
Nacogdoches, Texas 75961
Telephone: (936) 715-9333
Facsimile: (936) 715-9339
www.rankinlawfirm.com
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