Mirroring the Boot Disk
Mirroring the boot disk provides additional redundancy in both the management server and cluster nodes. The management server automatically mirrors its boot disk during the data center installation using Solaris Volume Manager software. The nodes are handled differently, depending upon the type of database installation you chose.
For Oracle9i RAC installations, the root disk on each node is encapsulated and mirrored using VxVM software. This mirroring is the only configuration possible.
For HA ORACLE data service, the boot disk is mirrored using the same software chosen to manage the globally accessible file systems: either VxVM software or Solaris Volume Manager software. Choose either of these, as is appropriate for your system.