"Volumes do not have typical status indicators" means that there is no common polling method to determine the status of the Volume. That is to say, there is no OID that we use where the device tells us the status of the volume. Many MIBs include a status OID that reports Up, Down, Running, etc. but volumes don't so we simply use the existence of a reply as the indicator of status.
Thus, the Up and Down status of a Volume is based on the existence of data from the Volume Description OID form the MIB rather than the device telling us if the volume is Up or Down explicitly.
Sorry for any confusion my comment may have caused. Also, as mentioned in this thread, the renaming of the volume is the most common cause of a volume going down.
Thanks
KZ
