То, как Вы удаляете, присоединило FC LUNS от CentOS 6?

Можете ли вы показать вывод df -h ?

В общем:

umount the volume's mount point

# Assuming Multipath, get the drives associated with the LUN [ie sdc, sdj etc]
multipath -l <mpathalias>

# Flush the multipath device
multipath -f <mpathalias>

# Verify that the above drives are no longer used by ANYTHING
# Do this for EACH drive
lsof /dev/sdX    #Where X = drive designation above

# Delete the drives.
# Do this for EACH drive
echo 1 > /sys/block/sdX/device/delete  #Where X = drive designation above

# Unmap the volume on the SAN

# Re-scan then list multipath to make sure it doesn’t find the volume
# you just removed
multipath
multipath -l