Time Machine - backup System Drive and External Drive to 2 partitions? Help

Question

Hi all, I'm a bit confused with Time Machine. Here's the situation:
I have my internal system drive (500GB) and an external FW drive (500GB). I have a backup drive (1TB). I would like to partition my backup drive and have Time Machine backup my system drive to partition 1, my external drive to partition 2. The Time Machine interface does not make it obvious how to do this. Is it possible? How?
Thanks!
js

Answer 1

js,
No, Time Machine will not do this. While it can back up both volumes, it will do so by creating two folders within the "Backups.backupdb" folder, each named for one of the volumes being backed up. In other words, it backs up both volumes to the single volume.
You'll need to carefully consider whether or not it makes sense to use it with both. Obviously, the backup drive (1 TB) will need to have just one partition to contain everything. Additionally, Time Machine really needs at least twice the amount of space required for the initial backup. Closer to 3X, if it can be managed. This is to insure that it will always have enough room to "do its thing" with subsequent backups. In order to evaluate this, you'll need to add the amount of data being stored on both source volumes, then estimate how much that data might change and/or grow over time. I would recommend strongly against using Time Machine to backup both volumes if you think the total might ever exceed 500 GBs (that is, the total used on the two source volumes). Even if you think it might come close, this would tend to recommend against using Time Machine.
If you really have the kind of data that fills up 2 500 GB drives, especially if one of those is your boot drive, you should seriously consider some hefty file management. This doesn't rule out Time Machine; quite the contrary. However, you'll need to separate your data into "live" data, and that which can be "archived." Your installation of OS X, all your applications, and your day-to-day "user files" would obviously be considered "live." To this total, you would add any files on which you might be working, in various "projects."
Anything and everything else is a strong candidate for "archival." These files would be best stored separately, where their need for constantly updated redundancy is eliminated. If they can be archived to DVDs, all the better (I would want to do this in addition to storing them on a relatively static and rarely used external drive).
If you adopt such a routine, you should realistically be able to whittle down your boot volume to no more than 100 GBs. Perhaps a little more if you are using Pro apps such as the CS suite, FCP, etc., along with their attendant template libraries.
Under such a scenario, Time Machine would work very well in backing up your boot volume and any external drive you would use for additional "live" project files. Everything else could be stored on an external drive that you would use only when you need access to the old archived data, and it could be made redundant by you, manually, as and when you see fit. Since this data would be and remain "static" in nature, it would not need regular and recurrent backup.
Scott
For example,