If connected to a server, a USB disk or Flash Drive can be accessed the same way as a "normal" hard drive.
To do this please proceed as follows:
1.) Use the "dmesg" command to check how the device has been detected. One of the latest entries should contain "/dev/sdX" (where 'X' stands for a random letter). In a two-disk system the USB drive usually is labeled "/dev/sdc".
2.) Format the drive with your desired file system. (Optional: Partition the drive to your liking first).
3.) Mount the drive to the desired directory (e.g. /data1). Please note that the directory you want to use already has to exist.
4.) Add a new mounting entry to the /etc/fstab file. This will mount the drive automatically after rebooting the system.