Anyway, i still like the idea of time machine, but how can i make it to not use all that space for archiving? I mean, i dont need 1 month old files to be there, actually i would like to use time machine for archiving lets say a week, and only my personal stuff since i will have a full backup with SD!. Can i do that? I mean, can i make it delete files after a week or so? Also, make it just archive my home folder? (pfff i might have to exclude every single folder exept my home folder)
There's some misinformation in this thread.
Does my backup hard drive have to be the same size or larger than my internal hard drive?
No. Time Machine doesn't care how big your backup drive is as long as it's large enough to store the initial backup. Therefore, if you have a 1TB internal drive and only a 500GB external drive, but only want to backup your home directory — you can — as long as the 500GB drive is large enough to sustain the initial backup.
Can I only use a certain portion of my backup hard drive for backups leaving the rest for other purposes?
Yes. You can partition your hard drive so that Time Machine only uses a certain amount of your backup hard drive for backups. For example, if you have a 1TB hard drive — you could partition it with Disk Utility to give you 500GB for Time Machine and 500GB for other purposes. At that point, Time Machine wouldn't use more than 500GB.
Can I just backup my home folder?
Yes. In order to just backup your home folder you're going to have to add all your other folders on your hard drive (Applications, Developer, Library, System) to the "Do Not Backup" dialog box under options in the Time Machine preference pane.
Can I prevent Time Machine from keeping older files?
Yes and No. By its nature, Time Machine prioritizes your most recent backups. Therefore, you could artificially limit the hard drive space available to Time Machine by partitioning (see above) to keep only your more recent files. However, there is no option to do this automatically. Time Machine by default will use all the available space on a drive (or partition) for backups.
Additionally, you could always do the initial backup and then turn off Time Machine. Then use the "Backup Now" feature whenever you wanted to update your backup. However, that is on you to remember to initialize subsequent backups.