Carbon Copy Cloner question

[gangof4]

I have no personal files on my iMac hard drive. I have two LaCie d2 external drives. One backs up via Time Machine and a second drive has my personal files. That second drive is also backed up automatically via Time Machine. I just got a third LaCie d2 to run carbon copy cloner, and it will be third in the Daisey chain (furthest from the computer.) After my initial hard drive copy should I leave it on or shut it off? If I leave it on, I will then have two backup of the system, one directly from the computer hard drive and the second from the external drive running CCC. Would that be a problem?