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Solaris 10 11/06 Installation Guide: Solaris Live Upgrade and Upgrade Planning

Procedurex86: To Fall Back From a Failed Boot Environment Activation With the GRUB Menu and the DVD or CD

If you experience a failure while booting, use the following procedure to fall back to the original boot environment. In this example, the new boot environment was not bootable. Also, the GRUB menu does not display. The device is /dev/dsk/c0t4d0s0. The original boot environment, c0t4d0s0, becomes the active boot environment.

Caution – Caution –

For the Solaris 10 3/05 release, the recommended action to fall back if the previous boot environment and new boot environment were on different disks included changing the hard disk boot order in the BIOS. Starting with the Solaris 10 1/06 release, changing the BIOS disk order is unnecessary and is strongly discouraged. Changing the BIOS disk order might invalidate the GRUB menu and cause the boot environment to become unbootable. If the BIOS disk order is changed, reverting the order back to the original settings restores system functionality.

  1. Become superuser or assume an equivalent role.

    Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

  2. Insert the Solaris Operating System for x86 Platforms DVD or Solaris Software for x86 Platforms - 1 CD.

  3. Boot from the DVD or CD.


    # init 6

    The GRUB menu is displayed.


    GNU GRUB version 0.95 (616K lower / 4127168K upper memory)
+-------------------------------------------------------------------+
|Solaris                                                            |
|Solaris failsafe                                                   |
+-------------------------------------------------------------------+
Use the ^ and v keys to select which entry is highlighted. Press
enter to boot the selected OS, 'e' to edit the commands before
booting, or 'c' for a command-line.

  4. Boot to single user mode by editing the Grub menu.

    1. To edit the GRUB main menu, type e.

      The GRUB edit menu is displayed.


      root (hd0,2,a)
kernel /platform/i86pc/multiboot
module /platform/i86pc/boot_archive

    2. Select the original boot environment's kernel entry by using the arrow keys.

    3. To edit the boot entry, type e.

      The kernel entry is displayed in an editor.


      grub edit>kernel /boot/multiboot

    4. Type -s and press Enter.

      The following example notes the placement of the -s option.


      grub edit>kernel /boot/multiboot -s

    5. To begin the booting process in single user mode, type b.

  5. If necessary, check the integrity of the root (/) file system for the fallback boot environment.


    # fsck mount_ point
    mount_point

    A root (/) file system that is known and reliable

  6. Mount the original boot environment root slice to some directory (such as /mnt): 


    # mount device_name /mnt
    device_name

    Specifies the location of the root (/) file system on the disk device of the boot environment you want to fall back to. The device name is entered in the form of /dev/dsk/cwtxdysz.

  7. From the active boot environment root slice, type:


    # /mnt/sbin/luactivate
Do you want to fallback to activate boot environment c0t4d0s0
(yes or no)? yes

    luactivate activates the previous working boot environment and indicates the result.

  8. Unmount /mnt.


    # umount device_name
    device_name

    Specifies the location of the root (/) file system on the disk device of the boot environment you want to fall back to. The device name is entered in the form of /dev/dsk/cwtxdysz.

  9. Reboot. 


    # init 6

    The previous working boot environment becomes the active boot environment.