Make sure that you have root privilege and that you have a current backup of all data.
Use one of the following methods to enable a slice in a submirror.
From the Enhanced Storage tool within the Solaris Management Console, open the Volumes node, choose the mirror, then choose Action->Properties and click the Submirrors tab. Follow the instructions on screen. For more information, see the online help.
Use the metareplace command to enable a failed slice in a submirror.
# metareplace -e mirror failed-slice
See the metareplace(1M) man page for more information.
# metareplace -e d11 c1t4d0s7 d11: device c1t4d0s7 is enabled
If a physical disk is defective, you can either replace it with another available disk (and its slices) on the system as documented in How to Replace a Slice in a Submirror. Alternatively, you can repair/replace the disk, format it, and run the metareplace command with the -e option as shown in this example.