x86: 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.

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.

   • For an installation with CD media:

     GNU GRUB version 0.95 (631K lower / 2095488K upper memory) +-------------------------------------------------------------------+ |Solaris Express 5/07 image_directory | |Solaris Express 5/07 Serial Console tty | |Solaris Express 5/07 Serial Console ttyb (for lx50, v60x and v65 | +-------------------------------------------------------------------+ 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.

   • For an installation with a DVD media:

     GNU GRUB version 0.95 (631K lower / 2095488K upper memory) +-------------------------------------------------------------------+ |Solaris Express 5/07 Developer Edition image_directory | |Solaris Express 5/07 | |Solaris Express 5/07 Serial Console ttya | |Solaris Express 5/07 Serial Console ttyb (for lx50, v60x and v65) | +-------------------------------------------------------------------+ 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. Wait for the default option to boot or choose any option displayed.

   The installation screen is displayed.

   • For CD media you see the following screen.

     +-------------------------------------------------------------------+ |Select the type of installation you want to perform: | | | | 1 Solaris Interactive | | 2 Custom JumpStart | | 3 Solaris Interactive Text (Desktop session) | | 4 Solaris Interactive Text (Console session) | | 5 Apply driver updates | | 6 Single user shell | | | | Enter the number of your choice followed by the <ENTER> key.| | Alternatively, enter custom boot arguments directly. | | | If you wait 30 seconds without typing anything, | | an interactive installation will be started. | +----------------------------------------------------------------- --+

   • For DVD media, you see the following screen.

   +--------------------------------------------------------------------+ |Select the type of installation you want to perform: | | | | 1 Solaris Interactive GUI | | 2 Apply driver updates | | 3 Single user shell | |Enter the number of your choice followed by the <ENTER> key. | |Alternatively, enter custom boot arguments directly. | | | | If you wait 30 seconds without typing anything, | | an interactive installation will be started. | +--------------------------------------------------------------------+

5. Choose the “Single user shell” option.

   The following message is displayed.

   Do you wish to automatically update the boot archive? y /n

6. Type: n

   Starting shell... #

   You are now in single user mode.

7. 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

8. 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.

9. 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.

10. 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.

11. Reboot.

    # init 6

    The previous working boot environment becomes the active boot environment.