VERITAS Volume Manager Storage Administrator (VMSA) allows sub-volumes of layered volumes (stripe-pro, concat-pro) to be unmirrored without warning of the irreversibility of the action
In VERITAS Volume Manager Storage Administrator (VMSA) versions prior to 3.2, it was possible to unmirror a sub-volume of a layered volume (stripe-pro or concat-pro) from the Volume Layout display. This action is not reversible and leaves the volume in a degraded state without an easy way to fix it.
1) Add a third mirror to the main volume using Volumes -> Mirror -> Add and then remove excess plexes from the other sub-volumes with Mirrors -> Remove Mirror from the Volume Layout menu bar.
2) Create a dummy volume, disassociate the plex, and then add the plex back into this volume: