If you use the detach keyword to detach a submirror, lucreate checks if a device is currently resyncing. If the device is resyncing, you cannot detach the submirror and you see an error message.
Resynchronization is the process of copying data from one submirror to another submirror after the following problems:
A submirror has been taken offline and brought back online.
The addition of a new submirror.
For more information about resynchronization, see RAID-1 Volume (Mirror) Resynchronization in Solaris Volume Manager Administration Guide.