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SLES 10 Storage Administration Guide
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vd
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during the install, it might be assigned to
/dev/sdg1
after the SAN is connected. One way to
avoid this problem is to use the UUID in the boot loader and
/etc/fstab
files for the boot
device.
A UUID never changes, no matter where the device is mounted, so it can always be found at boot. In
a boot loader file, you typically specify the location of the device (such as
/dev/sda1
or
/dev/
evms/sda1
) to mount it at system boot. The boot loader can also mount devices by their UUIDs
and administrator-specified volume labels. However, if you use a label and file location, you cannot
change the label name when the partition is mounted.
You can use the UUID as criterion for assembling and activating software RAID devices. When a
RAID is created, the
md
driver generates a UUID for the device, and stores the value in the
md
superblock.
3.2.2 Finding the UUID for a File System Device
You can find the UUID for any block device in the
/dev/disk/by-uuid
directory. For example,
a UUID looks like this:
e014e482-1c2d-4d09-84ec-61b3aefde77a
3.3 Using UUIDs in the Boot Loader and /etc/
fstab File (x86)
After the install, you can optionally use the following procedure to configure the UUID for the
system device in the boot loader and
/etc/fstab
files for your x86 system.
1
Install the SUSE
®
Linux Enterprise Server for x86 with no SAN devices connected.
2
After the install, boot the system.
3
Open a terminal console as the
root
user or equivalent.
4
Navigate to the
/dev/disk/by-uuid
directory to find the UUID for the device where you
installed
/boot
,
/root
, and
swap
.
4a
At the terminal console prompt, enter
cd /dev/disk/by-uuid
4b
List all partitions by entering
ll
4c
Find the UUID, such as
e014e482-1c2d-4d09-84ec-61b3aefde77a —> /dev/sda1
5
Edit
/boot/grub/menu.1st
file, using the Boot Loader option in YaST2 or using a text
editor.
For example, change
kernel /boot/vmlinuz root=/dev/sda1
to
kernel /boot/vmlinuz root=/dev/disk/by-uuid/e014e482-1c2d-4d09-
84ec-61b3aefde77a
IMPORTANT:
Make a copy of the original boot entry, then modify the copy. If you make a
mistake, you can boot the server without the SAN connected, and fix the error.
Summary of Contents for LINUX ENTERPRISE SERVER 10 - STORAGE ADMINISTRATION GUIDE 7-2007
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