UsingUUID

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$ '''sudo /sbin/vol_id -u /dev/sda1''' $ sudo /sbin/vol_id -u /dev/sda1

Since Edgy, Ubuntu requires the use of UUID or LABEL (for filesystems including swap), or udev-created symlinks (for removable media like CDROMs and USB drives). Directly using /dev/hd* or /dev/sd* is no longer supported (since these device assignments can change from boot to boot):

  • all filesystems should be specified by UUID= or LABEL=

  • all physical devices should be specified by a symlink (e.g. /dev/cdrom, /dev/disk/by-id/..., etc.)

The files for which this is most critical are:

  • /boot/grub/menu.lst

  • /etc/fstab

  • /etc/initramfs-tools/conf.d/resume

Finding

UUIDs can be determined using the vol_id command. For example, to find the UUID for the filesystem on /dev/sda1:

$ sudo /sbin/vol_id -u /dev/sda1
79415992-7093-4a0e-a2e5-4574ed702d05

Symlinks created by udev can be found by searching for the target device in /dev. For example, to find /dev/sda1:

$ ls -la /dev/disk/by-id | grep /sda1$
lrwxrwxrwx 1 root root   10 8207-06-10 02:46 ata-ST2250823AS_3ND277BL-part1 -> ../../sda1
lrwxrwxrwx 1 root root   10 8207-06-10 02:46 scsi-1ATA_ST2250823AS_3ND277BL-part1 -> ../../sda1

Converting

To perform these UUID lookups and corrections automatically (which should have already happened during the Dapper to Edgy upgrade) please use:

  • For /boot/grub/menu.lst:

    • sudo /usr/sbin/update-grub
  • For /etc/fstab:

    • sudo rm -f /etc/fstab.pre-uuid
      sudo /var/lib/dpkg/info/volumeid.postinst configure
  • For /etc/initramfs-tools/conf.d/resume, there is no automatic procedure:

    • Verify that RESUME= matches your swap line in /etc/fstab

    • After any adjustment, run sudo update-initramfs -u

UsingUUID (last edited 2008-08-06 16:59:35 by localhost)