Scusa, non riesco a montare il disco usb

[root@server ~]# dmesg | grep hd
SCSI device sda: 976773168 512-byte hdwr sectors (500108 MB)
SCSI device sda: 976773168 512-byte hdwr sectors (500108 MB)
SCSI device sdb: 976773168 512-byte hdwr sectors (500108 MB)
SCSI device sdb: 976773168 512-byte hdwr sectors (500108 MB)
forcedeth 0000:00:14.0: highdma pwrctl gbit lnktim desc-v3
SCSI device sdc: 5860466688 512-byte hdwr sectors (3000559 MB)
SCSI device sdc: 5860466688 512-byte hdwr sectors (3000559 MB)
il comando mount /dev/sdc
o
mount /dev/sdc mnt/bk-sme
non vanno
dove sbaglio, sono poco pratico, ho letto qui:
http://wiki.contribs.org/USBDisks, ma non risolvo.