Slackware 14.1 - Use persistent disk names in lilo and fstab before adding a second hard disk

Posted 11-07-2015 at 04:31 PM by gegechris99
Updated 11-08-2015 at 05:16 AM by gegechris99

Tags lilo

I recently added to a laptop a second SATA Hitachi hard disk (HDD) using a HDD caddy that replaced the CD/DVD drive. This second HDD was from an old laptop whose motherboard died and had a Windows Vista partition and a linux partition.

The first HDD (Toshiba) in the laptop was partitioned as follows:
/dev/sda1 for the swap
/dev/sda2 for the root directory of Slackware 14.1 64bit with ext4 filesystem

After adding the second HDD, the boot process failed because the first HDD was recognized as device /dev/sdb instead of /dev/sda. I couldn't find a way to reassign device /dev/sda to the first HDD. To solve that issue, I used persistent disk names for the device and partitions of the first HDD. More precisely, I used persistent disk Ids.

Persistent disk Ids are symlinks that are located in directory /dev/disk/by-id/. With one HDD (Toshiba), it showed:

Code:

ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT -> ../../sda
ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part1 -> ../../sda1
ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part2 -> ../../sda2
wwn-0x50000395f1e0380e -> ../../sda
wwn-0x50000395f1e0380e-part1 -> ../../sda1
wwn-0x50000395f1e0380e-part2 -> ../../sda2

The Toshiba HDD Ids linked to /dev/sda

Using permanent disk Id for the boot process

Basically I replaced /dev/sda and /dev/sda* by their permanent disk Id in the configuration files used in the boot process: /etc/lilo.conf and /etc/fstab.

I removed the second HDD and booted again my system to make the changes.

As I use the generic kernel, I first had to recreate the initrd file.

Code:

mkinitrd -c -k 3.10.17 -m ext4 -f ext4 -r /dev/disk/by-id/ata-ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part2 -o /boot/initrd.gz

The important change, here, is the -r option.

I then edited /etc/lilo.conf:

Code:

[...]
#boot = /dev/sda
boot = /dev/disk/by-id/ata-ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT
[...]
# Linux bootable partition config begins
image = /boot/vmlinuz-generic-3.10.17
# root = /dev/sda2
  root = /dev/disk/by-id/ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part2
  initrd = /boot/initrd.gz
  label = Slackware
  read-only
# Linux bootable partition config ends

and ran lilo to apply the changes.

Finally, I changed /etc/fstab:

Code:

/dev/disk/by-id/ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part1        swap             swap        defaults         0   0
/dev/disk/by-id/ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part2        /                ext4        defaults         1   1
[...]

I put back the second HDD and the boot process with two HDDs completed successfully.

Directory /dev/disk/by-id now shows:

Code:

ata-Hitachi_HTS541612J9SA00_SB3D04EWGDP29E -> ../../sda
ata-Hitachi_HTS541612J9SA00_SB3D04EWGDP29E-part1 -> ../../sda1
ata-Hitachi_HTS541612J9SA00_SB3D04EWGDP29E-part2 -> ../../sda2
ata-Hitachi_HTS541612J9SA00_SB3D04EWGDP29E-part3 -> ../../sda3
ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT -> ../../sdb
ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part1 -> ../../sdb1
ata-TOSHIBA_MQ01ABF050_Z4ATT4FPT-part2 -> ../../sdb2
wwn-0x50000395f1e0380e -> ../../sdb
wwn-0x50000395f1e0380e-part1 -> ../../sdb1
wwn-0x50000395f1e0380e-part2 -> ../../sdb2
wwn-0x5000cca54dc5c390 -> ../../sda
wwn-0x5000cca54dc5c390-part1 -> ../../sda1
wwn-0x5000cca54dc5c390-part2 -> ../../sda2
wwn-0x5000cca54dc5c390-part3 -> ../../sda3

Slackware 14.1 - Use persistent disk names in lilo and fstab before adding a second hard disk

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