Carbon Copy Cloner can be used to back up several Macs to one particular Mac on your network. This can be a good method of reducing the number of hard drives that you use for backup, and can also help you consolidate your data, making offsite backup easier. The following illustrates an example scenario.
Suppose you have a Mac mini on your home network (media server, file server, backup server, etc.) with two hard drives attached to it, "Backup" and "Offsite Backup." The "Backup" hard drive is a staging hard drive — it has a folder at the root level for each computer that you back up. When you initially set up the backup task on one system, you'll choose "Remote Macintosh" from CCC's Destination menu and configure the remote Macintosh information as:
IP address: 10.0.1.11
Path: /Volumes/Backup/John's iMac
Replace the IP address with that of your Mac mini. Repeat the procedure for each Mac, each backing up to its respective folders. Each of these machines is scheduled to back up to the "Backup" volume on a nightly basis, and the backup server is then configured to clone "Backup" to "Offsite backup" once a night (or very early in the morning) after all the other tasks have completed.
The "Offsite" part of the setup involves a pair of disks, each named "Offsite Backup". You'll keep one of these at home attached to your Mini, and the other can go to work, your fireproof safe, your neighbor's house &mdsah; anywhere that gives it a little bit of physical proximity from your own home. At the beginning or end of every week, simply detach the disk from your mini and take it to work with you, then take the other disk home and reattach it to your Mini. CCC will sync up all of the changes from the Backup disk to the Offsite Backup disk the next morning.
There are advantages and disadvantages to backing up to a folder on a remote volume (e.g. "Backup"). The main advantage is that you don't have to make a guess at how much space to allocate to partitions for each of the computers that you back up. There's one partition, and when space is tight you simply erase some of the archive folders or buy a larger hard drive.
You can't, however, boot from that hard drive because all the OSes are in sub folders. As an alternative, you could instead partition the "Backup" hard drive and configure each machine to back up directly to one of the partitions, e.g.:
IP address: 10.0.1.11
Path: /Volumes/John's Backup <-- root of the "John's Backup" partition
That partition will be bootable if you back up your entire hard drive to it (e.g. both the OS and your user data) and if the disk is properly partitioned. The bonus to this method is that you can get back to productivity very quickly should you have some sort of disk failure.