How to Record the Path to the Alternate Boot Device (Command Line)

When mirroring root (/), you might need the path to the alternate boot device later if the primary device fails.

Example -- SPARC: Recording the Alternate Boot Device Path

In this example, you would determine the path to the alternate root device by using the ls -l command on the slice that is being attached as the second submirror to the root (/) mirror.

# ls -l /dev/rdsk/c1t3d0s0
lrwxrwxrwx 1  root root  55 Mar 5 12:54  /dev/rdsk/c1t3d0s0 -> \ 
../../devices/sbus@1,f8000000/esp@1,200000/sd@3,0:a

Here you would record the string that follows the /devices directory: /sbus@1,f8000000/esp@1,200000/sd@3,0:a.

On some newer Sun hardware, you will be required to change the /devicesdirectory name from sd@ to disk@.

DiskSuite users who are using a system with Open Boot Prom can use the OpenBoot nvalias command to define a "backup root" devalias for the secondary root mirror. For example:

ok  nvalias backup_root /sbus@1,f8000000/esp@1,200000/sd@3,0:a

In the event of primary root disk failure, you then would only enter:

ok  boot backup_root

Example -- x86: Recording the Alternate Boot Device Path

In this example, you would determine the path to the alternate boot device by using the ls -l command on the slice that is being attached as the second submirror to the root (/) mirror.

# ls -l /dev/rdsk/c1t0d0s0
lrwxrwxrwx 1  root root  55 Mar 5 12:54  /dev/rdsk/c1t0d0s0 -> ../.
./devices/eisa/eha@1000,0/cmdk@1,0:a

Here you would record the string that follows the /devices directory: /eisa/eha@1000,0/cmdk@1,0:a