My iTunes stores my OS X, iPhone and iPad settings. I got this kind of problem in OS X that stores the essential things such as settings and backups. According to this thread here, I need to format the drive.

The segregation of the HDD means I need to backup my OSx to some external HDD. Could someone suggest a storage? I have no idea which features to look for in backup disks, could someone guide me? Write-speed, read-speed, durability, something else? In the past, I have by accident broken 3.5 drives so I think I must get some cases such as here -- if I am going with traditional way.
Now in the Apple way:
What are the Apple ways to solve this backup problem?
Helper questions
Instead of buying 3.5" drives, I have wondered whether Apple offers something here: I will soon have a Mac Mini for rendering so could I use its storage for backup-storage?
I haven't yet used Time Machine, could I do this with it? Or should I take an image of the whole disk somehow?
If I go with some random HDD such as this here, what kind of features should I look for? Are all harddrives Apple-compatible? I have this kind of reader here.
