Problema nel montare un disco USB

[alghouti]

Ciao a tutti, spero di trovare la dritta giusta per superare il mio problema.

Vorrei monatre un LaCie Ethernet Big Disk via USB al mio Lacie Storage.
Aggiungo qualche dato (disco già collegato):

# uname -a
Linux NAS1 2.6.10-iop1-9 #1 Thu Nov 2 21:34:13 CST 2006 armv5tel unknown

#dmesg
Initializing USB Mass Storage driver...
usbcore: registered new driver usb-storage
USB Mass Storage support registered.
usb 1-5: new high speed USB device using ehci_hcd and address 2
usb 1-5: configuration #1 chosen from 2 choices

#mount
/dev/md0 on / type ext3 (rw)
none on /proc type proc (rw,nodiratime)
none on /sys type sysfs (rw)
/dev/vbdi2 on /nas/NASDisk-00002 type xfs (rw,nosuid,usrquota)
none on /proc/bus/usb type usbfs (rw)

# more /etc/fstab
/dev/md0 / ext3 defaults 1 1
none /proc proc defaults 0 0
none /sys sysfs defaults 0 0
/dev/sda2 swap swap defaults 0 0

Ora vorrei capire quale device devo montare...

Facendo il classico:
# mount /dev/sdb1 /mnt/usb/
mount: Mounting /dev/sdb1 on /mnt/usb failed: Device or resource busy

Ringraziando tutti in anticipo, attendo fiducioso...

Al