Rescan for usb

Sometimes the usb drive is disconnected you can try the following

[edit] Redhat Based

You may need to force an unmount

umount -f -l /mnt/usbstorage/location

Rescan SCSI channels

scsi_id

or possibly (usually not needed)

scsi_id -d /dev/sdb1

Then run fdisk to see if it see the drive

fdisk -l

Then run

blkid

Then mount the drive

Note: Remember to find the /dev/location from fdisk -l command for usb storage etc.

mount /dev/sdb1 /mnt/new/usbstorage/location

IE:

mount /dev/sdb1 /data/usbstorage
mount /dev/sde1 /data/usbstorage1
mount /dev/sdf1 /data/usbstorage2