QUESTION :
I am using Ubuntu Server 10 for LAMP and hosting sites.
I’ve added a second HDD for backups, but as the Server 10 runs without GUI, I don’t know now how to access/configure backups to the second HDD without GUI.
ANSWER :
Depending on what you mean by “access” it you might find this useful.
You might also find information on ZFS interesting, which you can find here
You can use sudo fdisk -l to see if your drive is there.
EDIT: Use the above fdisk command to get the drive name. It will be something like /dev/sdb2 (for example).
Using the first link provided you can follow steps to mount your drive to a location and access it from there. From that point you can attach whatever you wish to it.
This page Installing A New Hard Drive on the Ubuntu Community Help Wiki provides help for GUI and command line installation of a new Hard Drive