[SOLVED] Ubuntu Karmic: How do I use the sdX naming scheme instead of UUID?

lupusarcanus · 03-15-2010, 02:32 AM

Hey all.

I deciphered that I would have to change the /etc/fstab and grub.conf.

So the question is:

1: Which files must I edit?
2: How do I edit grub.conf to use the sdX scheme?

Thanks in advance.

Simon Bridge · 03-15-2010, 02:42 AM

In Karmic, you do not expect to find a grub.conf or a menu.lst - it uses grub2 - the file is grub.cfg and you do not usually edit it directly.

So you need to learn how to use grub2.
http://ubuntuforums.org/showthread.php?t=1195275

You can just use the old /dev/sdx scheme in fstab as usual. you are better to learn how to use uuids.
http://ubuntuforums.org/showthread.php?t=349376

If your problem is related to the way karmic mounts usb drives then see:
http://subbass.blogspot.com/2009/11/...-mounting.html

It sounds like you are trying to do something sub-optimally. What do you want to achieve?

lupusarcanus · 03-15-2010, 02:47 AM

Here is my /etc/fstab:

Code:

# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=093db984-d6ef-464e-bbfb-2bc46720edfb /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=dcc6af3c-c450-45fe-bafd-bdb5111a479d none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec,utf8 0       0

<Using legacy GRUB now>
<Please see the nest post>

I am confused because I do not know how to edit the /etc/fstab correctly (I don't want to screw anything up), and the files pointed to by grub.cfg don't give me any ideas how to switch to sdX.

EDIT: @Simon Bridge; 1. sdX is a more vanilla naming scheme; 2. So I can use a 'universal' swap when I install another distro. Last time I let Ubuntu keep the UUID's, and the system hung infinitely on boot.

EDIT: @Simon Bridge; If there is no performance loss, then I would rather have sdX, as I like it better.

lupusarcanus · 03-15-2010, 03:17 AM

Thanks to the investigative work of Simon Bridge, I fell back to a more familiar legacy GRUB, which turns out to be much faster than GRUB2.

Anyways, please excuse the sudden change, and disregard the grub.cfg contents. Thank You. Here is the new, improved and much easier to edit menu.lst:

Code:

# menu.lst - See: grub(8), info grub, update-grub(8)
#            grub-install(8), grub-floppy(8),
#            grub-md5-crypt, /usr/share/doc/grub
#            and /usr/share/doc/grub-doc/.

## default num
# Set the default entry to the entry number NUM. Numbering starts from 0, and
# the entry number 0 is the default if the command is not used.
#
# You can specify 'saved' instead of a number. In this case, the default entry
# is the entry saved with the command 'savedefault'.
# WARNING: If you are using dmraid do not use 'savedefault' or your
# array will desync and will not let you boot your system.
default		0

## timeout sec
# Set a timeout, in SEC seconds, before automatically booting the default entry
# (normally the first entry defined).
timeout		0

## hiddenmenu
# Hides the menu by default (press ESC to see the menu)
hiddenmenu

# Pretty colours
#color cyan/blue white/blue

## password ['--md5'] passwd
# If used in the first section of a menu file, disable all interactive editing
# control (menu entry editor and command-line)  and entries protected by the
# command 'lock'
# e.g. password topsecret
#      password --md5 $1$gLhU0/$aW78kHK1QfV3P2b2znUoe/
# password topsecret

#
# examples
#
# title		Windows 95/98/NT/2000
# root		(hd0,0)
# makeactive
# chainloader	+1
#
# title		Linux
# root		(hd0,1)
# kernel	/vmlinuz root=/dev/hda2 ro
#

#
# Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST

### BEGIN AUTOMAGIC KERNELS LIST
## lines between the AUTOMAGIC KERNELS LIST markers will be modified
## by the debian update-grub script except for the default options below

## DO NOT UNCOMMENT THEM, Just edit them to your needs

## ## Start Default Options ##
## default kernel options
## default kernel options for automagic boot options
## If you want special options for specific kernels use kopt_x_y_z
## where x.y.z is kernel version. Minor versions can be omitted.
## e.g. kopt=root=/dev/hda1 ro
##      kopt_2_6_8=root=/dev/hdc1 ro
##      kopt_2_6_8_2_686=root=/dev/hdc2 ro
# kopt=root=UUID=093db984-d6ef-464e-bbfb-2bc46720edfb ro

## default grub root device
## e.g. groot=(hd0,0)
# groot=093db984-d6ef-464e-bbfb-2bc46720edfb

## should update-grub create alternative automagic boot options
## e.g. alternative=true
##      alternative=false
# alternative=true

## should update-grub lock alternative automagic boot options
## e.g. lockalternative=true
##      lockalternative=false
# lockalternative=false

## additional options to use with the default boot option, but not with the
## alternatives
## e.g. defoptions=vga=791 resume=/dev/hda5
# defoptions=quiet splash

## should update-grub lock old automagic boot options
## e.g. lockold=false
##      lockold=true
# lockold=false

## Xen hypervisor options to use with the default Xen boot option
# xenhopt=

## Xen Linux kernel options to use with the default Xen boot option
# xenkopt=console=tty0

## altoption boot targets option
## multiple altoptions lines are allowed
## e.g. altoptions=(extra menu suffix) extra boot options
##      altoptions=(recovery) single
# altoptions=(recovery mode) single

## controls how many kernels should be put into the menu.lst
## only counts the first occurence of a kernel, not the
## alternative kernel options
## e.g. howmany=all
##      howmany=7
# howmany=all

## specify if running in Xen domU or have grub detect automatically
## update-grub will ignore non-xen kernels when running in domU and vice versa
## e.g. indomU=detect
##      indomU=true
##      indomU=false
# indomU=detect

## should update-grub create memtest86 boot option
## e.g. memtest86=true
##      memtest86=false
# memtest86=true

## should update-grub adjust the value of the default booted system
## can be true or false
# updatedefaultentry=false

## should update-grub add savedefault to the default options
## can be true or false
# savedefault=false

## ## End Default Options ##

title		Ubuntu 9.10, kernel 2.6.31-20-generic
uuid		093db984-d6ef-464e-bbfb-2bc46720edfb
kernel		/boot/vmlinuz-2.6.31-20-generic root=UUID=093db984-d6ef-464e-bbfb-2bc46720edfb ro quiet splash 
initrd		/boot/initrd.img-2.6.31-20-generic

title		Ubuntu 9.10, kernel 2.6.31-20-generic (recovery mode)
uuid		093db984-d6ef-464e-bbfb-2bc46720edfb
kernel		/boot/vmlinuz-2.6.31-20-generic root=UUID=093db984-d6ef-464e-bbfb-2bc46720edfb ro  single
initrd		/boot/initrd.img-2.6.31-20-generic

title		Ubuntu 9.10, kernel 2.6.31-14-generic
uuid		093db984-d6ef-464e-bbfb-2bc46720edfb
kernel		/boot/vmlinuz-2.6.31-14-generic root=UUID=093db984-d6ef-464e-bbfb-2bc46720edfb ro quiet splash 
initrd		/boot/initrd.img-2.6.31-14-generic

title		Ubuntu 9.10, kernel 2.6.31-14-generic (recovery mode)
uuid		093db984-d6ef-464e-bbfb-2bc46720edfb
kernel		/boot/vmlinuz-2.6.31-14-generic root=UUID=093db984-d6ef-464e-bbfb-2bc46720edfb ro  single
initrd		/boot/initrd.img-2.6.31-14-generic

title		Ubuntu 9.10, memtest86+
uuid		093db984-d6ef-464e-bbfb-2bc46720edfb
kernel		/boot/memtest86+.bin

### END DEBIAN AUTOMAGIC KERNELS LIST

How do I change this to use sdX instead? Thanks guys for your outstanding help, especially Simon Bridge.

linuxlover.chaitanya · 03-15-2010, 03:45 AM

If you want to know uuids, you can check /dev/disk directory and find out the uuids.

Simon Bridge · 03-15-2010, 08:46 AM

Quote:

How do I change this [menu.lst] to use sdX instead?

man menu.lst

Figure out which partitions are what and substitute the hd(x,y) or sdx for the uuids. Remember how menu.lst used to look? If not, just search LQ or google for an example.
http://ubuntuforums.org/showthread.php?t=226183

title Ubuntu 9.10, kernel 2.6.31-20-generic
%uuid 093db984-d6ef-464e-bbfb-2bc46720edfb %%% if this is /dev/sda1 normally
root (hd0,0)
kernel /boot/vmlinuz-2.6.31-20-generic root=/dev/sda1 ro quiet splash
initrd /boot/initrd.img-2.6.31-20-generic

http://fixunix.com/mandriva/531323-u...eir-value.html
... discussion on uuids, devfs labels and disk labels.

http://ubuntuforums.org/showthread.php?t=1302743
... using grub2 in ubuntu.

lupusarcanus · 03-15-2010, 03:30 PM

Quote:

Originally Posted by Simon Bridge

man menu.lst

Figure out which partitions are what and substitute the hd(x,y) or sdx for the uuids. Remember how menu.lst used to look? If not, just search LQ or google for an example.
http://ubuntuforums.org/showthread.php?t=226183

title Ubuntu 9.10, kernel 2.6.31-20-generic
%uuid 093db984-d6ef-464e-bbfb-2bc46720edfb %%% if this is /dev/sda1 normally
root (hd0,0)
kernel /boot/vmlinuz-2.6.31-20-generic root=/dev/sda1 ro quiet splash
initrd /boot/initrd.img-2.6.31-20-generic

http://fixunix.com/mandriva/531323-u...eir-value.html
... discussion on uuids, devfs labels and disk labels.

http://ubuntuforums.org/showthread.php?t=1302743
... using grub2 in ubuntu.

Thanks; successfully am using sdX instead of UUID.

The reason why I like sdX is it's easier to administer to when I have a problem. I don't use RAID arrays or LVMs, and all USB attached devices always show up as the /dev/sdb. It's a very clean and easy way to diagnose potential problems when they occur. Like you said, and I forgot

, there is plenty of documentation for legacy GRUB as well.

Although I used your example and set up the menu.lst, I tried your suggestion of man menu.lst and received no manual entry.

Anyways, this thread is SOLVED. Thank you Simon Bridge for your help.

Simon Bridge · 03-15-2010, 11:52 PM

Great to hear.

I included the uuid and grub2 links for future readers rather than you. sdx is conceptually easier than uuids and and similarly grub to grub2, if you don't need the extra power why have it?

Usually if you install grub you get man pages to go with it. Oh well, it worked anyway.