Tape drive is not visible on Redhat 6.5

Hi Experts,

server is running with Red Hat Enterprise Linux Server release 6.5 on HP ProLiant DL380p. The tape drives are connected from Sun storage Tek and when we list the tape drives with lsscsi -g | grep -i tape could see all the tape drives connect with this particular server. But when we pull the tape drive info with the help of data protector command /opt/omni/lbin/devbra -dev could see different in tape drive count. And the difference (number of drive counts} most of the time varies.