You can enable a component when any of the following conditions exist:
Solaris Volume Manager could not access the physical drive. This problem might have occurred, for example, due to a power loss, or a loose drive cable. In this case, Solaris Volume Manager puts the components in the “Maintenance” state. You need to make sure that the drive is accessible (restore power, reattach cables, and so on), and then enable the components in the volumes.
You suspect that a physical drive is having transitory problems that are not disk-related. You might be able to fix a component in the “Maintenance” state by simply enabling it. If this does not fix the problem, then you need to either physically replace the disk drive and enable the component, or replace the component with another available component on the system.
When you physically replace a drive, be sure to partition it like the old drive to ensure adequate space on each used component.
Always check for state database replicas and hot spares on the drive being replaced. Any state database replica shown to be in error should be deleted before replacing the disk. Then after enabling the component, they should be re-created (at the same size). You should treat hot spares in the same manner.