Hello all, i have 2 questions about time machine today.
1. How much space does it use to back up?--does it get larger and larger as you put more stuff in your drive to back up, or does it allocate a certain amount then fill it?
2. Is it possible to backup 2 different macs on the same external drive?
Thanks in advanced for your help,
GF
1. TM backs up everything and maintains archives of your system over time. In theory, your backup system will grow over time until it is full. At that point, you should change your backup drive.
My internal hard drive is 250G. My backup, an internal hard disk in an external drive box, is a 500G drive. I figure I'm good for at least 6 months and probably a year. (Realistically it's probably longer than that, but I like to be conservative on such estimates.)
2. You could probably do that if you want, but I wouldn't recommend it. Whatever drive you have should probably be 2x the total drive space between the two machines. If you try this, you'll have to experiment to see how well Leopard maintains archives for the two machines.
One issue I see is that you are depending on one drive to backup two systems. If that drive fails, you're potentially in trouble. Backups for both systems are lost at that point, and you are no longer protected against failures of your machines.
Another issue I see is that you cannot connect your backup drive to both machines at the same time. To backup both machines, you'll need to regularly switch your external drive between both machines. At some point you'll probably stop doing it, unless the machines are typically side-by-side.
Apple suggests you not use your backup drive for storing other files, so using one drive to backup two machines is probably a Bad Thing. My guess is that you can do it, but it's not a good idea.
My recommendation would be to have a separate backup drive for each system. This reduces the likelihood of losing all of your backups, and helps to ensure you'll maintain good backups for both systems.
Hope this helps!