VxVM can place various files from the root file system, swap device, and other file systems on the root disk under VxVM control. This is called rootability. The root disk (that is, the disk containing the root file system) can be put under VxVM control through the process of encapsulation.
See Encapsulating a disk.
Encapsulation converts existing partitions on that disk to volumes. Once under VxVM control, the root and swap devices appear as volumes and provide the same characteristics as other VxVM volumes. A volume that is configured for use as a swap area is referred to as a swap volume, and a volume that contains the root file system is referred to as a root volume.
It is possible to mirror the rootvol, and swapvol volumes, as well as other parts of the root disk that are required for a successful boot of the system (for example, /usr). This provides complete redundancy and recovery capability in the event of disk failure. Without VxVM rootability, the loss of the root, swap, or usr partition prevents the system from being booted from surviving disks.
Mirroring disk drives that are critical to booting ensures that no single disk failure renders the system unusable. A suggested configuration is to mirror the critical disk onto another available disk (using the vxdiskadm command). If the disk containing root and swap partitions fails, the system can be rebooted from a disk containing mirrors of these partitions.