A system crash or an I/O error can corrupt one or more plexes of a mirrored volume and leave no plex CLEAN or ACTIVE. You can mark one of the plexes CLEAN and instruct the system to use that plex as the source for reviving the others.
To recover an unstartable mirrored volume
# vxmend [-g diskgroup] fix clean plex
For example, to place the plex vol01-02 in the CLEAN state:
# vxmend -g mydg fix clean vol01-02
# vxmend [-g diskgroup] fix stale plex
Following severe hardware failure of several disks or other related subsystems underlying all the mirrored plexes of a volume, it may be impossible to recover the volume using vxmend. In this case, remove the volume, recreate it on hardware that is functioning correctly, and restore the contents of the volume from a backup or from a snapshot image.
See the vxmend(1M) manual page.
# vxvol [-g diskgroup] start volume
For example, to recover volume vol01:
# vxvol -g mydg start vol01
See the vxvol(1M) manual page.