In this example, you 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/dsk/c1t3d0s0 lrwxrwxrwx 1 root root 55 Mar 5 12:54 /dev/rdsk/c1t3d0s0 -> \ ../../devices/sbus@1,f8000000/esp@1,200000/sd@3,0:a |
Record the string that follows the /devices directory: /sbus@1,f8000000/esp@1,200000/sd@3,0:a.
Edit the string to change the major name (sd, in this case) to disk, resulting in /sbus@1,f8000000/esp@1,200000/disk@3,0:a. If the system uses an IDE bus, the original full path might look like
$ ls -l /dev/dsk/c0t0d0s0 lrwxrwxrwx 1 root root 38 Mar 13 15:03 /dev/dsk/c0t0d0s0 -> \ ../../devices/pci@1f,0/ide@d/dad@0,0:a |
After changing the major name dad to disk, you would have /pci@1f,0/ide@d/disk@0,0:a
You can use the OpenBootTM Prom nvalias command to define a “backup root” device alias for the secondary root (/) mirror. For example:
ok nvalias backup_root /sbus@1,f8000000/esp@1,200000/disk@3,0:a |
Then, redefine the boot-device alias to reference both the primary and secondary submirrors, in the order in which you want them to be used, and store the configuration.
ok printenv boot-device boot-device = disk net ok setenv boot-device disk backup-root net boot-device = disk backup-root net ok nvstore |
In the event of primary root disk failure, the system would automatically boot to the second submirror. Or, if you boot manually, rather than using auto boot, you would only enter:
ok boot backup_root |