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brfransen, 06/07/2010 01:13 pm


Upgrade to LinHES from KnoppMyth R5

Convert /etc/fstab to use UUIDs

If you have multiple hard drives before upgrading to LinHES, you will need to modify your /etc/fstab to use the UUID of the hard drives in your system. As in the past, during an upgrade the installer inspects the root partition for this file and uses it to setup mount points. However, because R6 uses the modern SCSI emulation layer drivers for all hard drives, what used to be /dev/hdb1 is now /dev/sdb1, or possibly /dev/sda1, or /dev/sdc1, or ... Well you get the picture...

Using the UUID of the hard drive is the best way to solve the problem. For example, this is what the fstab entries for my HD and LVM volumes look like using labels:

/etc/fstab:

LABEL=Root    /           ext3  defaults,errors=remount-ro  0  1

LABEL=myth    /myth       auto  defaults,auto  0  2

LABEL=swap1   none        swap  defaults  0  0

This is what they'd look like using UUID:

/etc/fstab:

UUID=24f28fc6-717e-4bcd-a5f7-32b959024e26  /           ext3  defaults,errors=remount-ro  0  1

UUID=03ec5dd3-45c0-4f95-a363-61ff321a09ff  /myth       auto  defaults,auto  0  2

UUID=4209c845-f495-4c43-8a03-5363dd433153  none        swap  defaults  0  0

Note that the only change is to replace the device names with the appropriate UUID identifiers.

Hint: running blkid will list the UUIDs for all of your partitions and volumes. E.g.:

root@black2:~# blkid
/dev/hda1: LABEL="Root" UUID="24f28fc6-717e-4bcd-a5f7-32b959024e26" SEC_TYPE="ext2" TYPE="ext3" 

/dev/hda2: LABEL="swap1" UUID="4209c845-f495-4c43-8a03-5363dd433153" TYPE="swap" 

/dev/mapper/vg-myth: LABEL="myth" UUID="03ec5dd3-45c0-4f95-a363-61ff321a09ff" SEC_TYPE="ext2" TYPE="ext3" 

Hostname

Make a note of your current hostname. This is very important, since changing the hostname can make various DB entries keyed by hostname useless.
This command will print your hostname:

hostname

Backup

Make a backup and verify that it worked. The less time between when you make the backup and when you do the upgrade, the better. If the delay is more than a couple hours, you should verify that the backup is still current. You can't do a successful upgrade without a valid and up to date backup!

Install LinHES