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Booting from an alternate boot disks

If the root disk is encapsulated and mirrored, you can use one of its mirrors to boot the system if the primary boot disk fails. On a Sun SPARCR system, booting from an alternate boot disk requires that some EEPROM settings are changed.

See The boot process on Sun SPARC systems.

 To boot from an alternate boot disk on a Sun SPARC system

1. Check that the EEPROM variable use-nvramrc? is set to true by entering the following command at the boot prompt:

   ok printenv use-nvramrc?

   If set to true, this variable allows the use of alternate boot disks. To set the value of use-nvramrc? to true, enter the following command at the boot prompt:

   ok setenv use-nvramrc? true

   If use-nvramrc? is set to false, the system fails to boot from the devalias and displays an error message such as the following:

   Rebooting with command: boot vx-mirdisk

   Boot device: /pci@1f,4000/scsi@3/disk@0,0 File and args:vx-

   mirdisk

   boot: cannot open vx-mirdisk

   Enter filename [vx-mirdisk]:

2. Check for available boot disk aliases using the following command at the boot prompt:

   ok devalias

   Suitable mirrors of the root disk are listed with names of the form vx-diskname.

3. Enter this command:

   ok boot alias

   where alias is the name of an alternate root mirror.

   If a selected disk contains a root mirror that is stale, vxconfigd displays an error stating that the mirror is unusable and lists any non-stale alternate bootable disks.