I just built a new computer for WHS 2011. It has two 2TB internal drives and two 2TB USB external drives for backup. On my D: drive are photos/videos/important files. On my E: drive are movie rips and music. The E: drive is almost full so I will need to start adding my new movies and music to the D: drive. I would love for WHS to backup my D: drive to one external drive and my E: drive to the other external drive. I can't figure out how to do this. After giving up I figured that WHS will just use the full 4TB of external space and make a giant image of both of my internal drives. When I came home for lunch it was sitting at 53% complete. When I came home from work this evening it said the backup failed due to storage space. You can see from the attached image (please click it to full-screen) that the 2nd external drive wasn't even touched. What do I need to do?

I do have a secondary question. When WHS 2011 does its backups does it do an entire backup or will it see that I haven't added any movies in the last day and not even bother with the E: drive? I think I may just turn auto backups off and only do a backup on the nights where I actually add files to the server. I have no need for WHS to backup any client computers. My main PC has a small 96GB SSD with only Win7 on it, Office and a game or two. Everything else will go on the WHS.
Thanks in advance for any help!

I do have a secondary question. When WHS 2011 does its backups does it do an entire backup or will it see that I haven't added any movies in the last day and not even bother with the E: drive? I think I may just turn auto backups off and only do a backup on the nights where I actually add files to the server. I have no need for WHS to backup any client computers. My main PC has a small 96GB SSD with only Win7 on it, Office and a game or two. Everything else will go on the WHS.
Thanks in advance for any help!