/usr file system is defined on a mirrored volume, errors in the partition that underlies one of the mirrors can result in data corruption or system errors at boot time (when VxVM is started and assumes that the mirrors are synchronized).
The following workarounds exist for this situation:
/usr file system, repair it, unmount it, and use
dd to copy the fixed plex to all other plexes. This procedure is not recommended as it can be error prone.