[linux-lvm] Re: linux-lvm digest, Vol 1 #602 - 14 msgs

[linux-lvm] Re: linux-lvm digest, Vol 1 #602 - 14 msgs

[James B. Byrne]

On Thu, 30 May 2002 19:45:33 +0200
Thierry DE CARVALHO <thierry.decarvalho@online.fr> wrote:

> Try with grub (here /dev/vg00/lvol1 is the root fs):
> 
> title=GNU/Linux Debian 2.2 (potato)
> kernel (hd0,1)/vmlinuz-2.2.19 root=3a00 ramdisk_size=8192 vga=10
> #                                   ^^^^ <major><minor> of the lv
> #                                   device
> in hex
> initrd (hd0,1)/initrd-lvm-2.2.19.gz

I am afraid that this does not make a lot of sense to me.  Where 
does one get the major/minor numbers for the logical volume?

Regards,
Jim
---     e-mail is NOT a secure channel 
James B. Byrne                mailto:ByrneJB@Harte-Lyne.ca
Harte & Lyne Limited          http://www.harte-lyne.ca
9 Brockley Drive              vox: +1 905 561 1241
Hamilton, Ontario             fax: +1 905 561 0757
Canada  L8E 3C3

Re: [linux-lvm] Re: linux-lvm digest, Vol 1 #602 - 14 msgs

[Kirby C. Bohling]

bash> cat /proc/lvm/VGs/data/LVs/develop


name:         /dev/data/develop
size:         20971520
access:       3
status:       1
number:       3
open:         1
allocation:   2
device:       58:03

(My VG is data, my LV is develop), the last line has the device number on it.


The other place to look is:

bash> ls -la /dev/data/develop

brw-rw----    1 root     disk      58,   3 Apr 12 17:56 develop

58,3 is (major, minor).  The trick is figuring out which ones are decimal, and 
which ones are hex.  I believe the ls -la are decimal, but when you put it in 
for root= it has to be in hex.

In this case, I believe 58 is the major, and 3 is the minor.
(I could be completely wrong on that decimal/hex thing, I just remember that 
being an issue for me in the past when looking at root= on the command line once 
in the past).

Ahhh, looking a bit more:

bash> stat /dev/data/develop

   File: "/dev/data/develop"
   Size: 0               Blocks: 0          IO Block: 4096   Block Device
Device: 309h/777d       Inode: 16521       Links: 1     Device type: 3a,3
Access: (0660/brw-rw----)  Uid: (    0/    root)   Gid: (    6/    disk)
Access: Fri Apr 12 17:56:53 2002
Modify: Fri Apr 12 17:56:53 2002
Change: Fri Apr 12 17:56:53 2002

Which would confirm that root= must be in hex, 3a (hex) = 58 (decimal).  It has 
to be 4 digits long so in this case it would be "root=3a03".  The Device Type: 
is where the 3a03 comes from...

	Hope this helps.


		Kirby


James B. Byrne wrote:
> On Thu, 30 May 2002 19:45:33 +0200
> Thierry DE CARVALHO <thierry.decarvalho@online.fr> wrote:
> 
> 
>>Try with grub (here /dev/vg00/lvol1 is the root fs):
>>
>>title=GNU/Linux Debian 2.2 (potato)
>>kernel (hd0,1)/vmlinuz-2.2.19 root=3a00 ramdisk_size=8192 vga=10
>>#                                   ^^^^ <major><minor> of the lv
>>#                                   device
>>in hex
>>initrd (hd0,1)/initrd-lvm-2.2.19.gz
> 
> 
> I am afraid that this does not make a lot of sense to me.  Where 
> does one get the major/minor numbers for the logical volume?
> 
> Regards,
> Jim
> ---     e-mail is NOT a secure channel 
> James B. Byrne                mailto:ByrneJB@Harte-Lyne.ca
> Harte & Lyne Limited          http://www.harte-lyne.ca
> 9 Brockley Drive              vox: +1 905 561 1241
> Hamilton, Ontario             fax: +1 905 561 0757
> Canada  L8E 3C3
> 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html

[linux-lvm] Re: Red Hat 7.3 lvm 1.03

[James B. Byrne]

On 3 Jun 2002 at 13:52, Kirby C. Bohling wrote:

> bash> stat /dev/data/develop
> 
>    File: "/dev/data/develop"
>    Size: 0               Blocks: 0          IO Block: 4096   Block
> Device Device: 309h/777d       Inode: 16521       Links: 1     Device
> type: 3a,3 Access: (0660/brw-rw----)  Uid: (    0/    root)   Gid: (  
>  6/    disk) Access: Fri Apr 12 17:56:53 2002 Modify: Fri Apr 12
> 17:56:53 2002 Change: Fri Apr 12 17:56:53 2002
> 
> Which would confirm that root= must be in hex, 3a (hex) = 58
> (decimal). It has to be 4 digits long so in this case it would be
> "root=3a03".  The Device Type: is where the 3a03 comes from...
> 
>  Hope this helps.

Oh yes, it helps a great deal.  Thank you very much.  This is what I 
get from /proc/lvm/VGs/vg00/LVs/lv01.  "lv01" is the name I gave to 
the root lv, but having a little more experience now I may change it 
to simply "root" or "rootfs" as this makes things a lot more clear 
when looking at the device entries.

My entry for lv01 (not currently mounted) says this:

# cat lv01
name:         /dev/vg00/lv01
size:         12288000
access:       3
status:       1
number:       0
open:         0
allocation:   0
device:       58:00

So using your example then this would work out to a major:minor 
number (in hex) of 3a:00, this then would go into my grub.conf 
thusly (as I understand your instructions):

title Red Hat Linux (2.4.18-4) lvm root file system
        root (hd0,0)
        kernel /vmlinuz-2.4.18-4 ro root=3a00 ramdisk_size=8192
        initrd /initrd-lvm-2.4.18-4.gz

instead of:

title Red Hat Linux (2.4.18-4) lvm root file system
        root (hd0,0)
        kernel /vmlinuz-2.4.18-4 ro ramdisk_size=8192 
root=/dev/vg00/lv01
        initrd /initrd-lvm-2.4.18-4.gz

Have I got this right now?

Regards,
Jim---     e-mail is NOT a secure channel 
James B. Byrne                mailto:ByrneJB@Harte-Lyne.ca
Harte & Lyne Limited          http://www.harte-lyne.ca
9 Brockley Drive              vox: +1 905 561 1241
Hamilton, Ontario             fax: +1 905 561 0757
Canada  L8E 3C3