In theory you can plug an external drive into the Airport Extreme and use it for TM.. in practice it is known to be unstable.. at least that is what guru level people here report.. I haven't personally tried.. but I accept what the guru says.
Read comments from Pondini.. guru to the guru.. head grand poobaah..
Pay attention.. because setting all this up and having the backups fail in a month will be a total waste of your time.
Time Capsule is a device apple designed for TM backups.. I have no idea why it works better than AEBS and usb disk, but there you go.. it does. The TC can have USB drives plugged into it.
If you had a desktop, I would have said just plug the external drives into it and make it available to the network.. but having drives plugged into a laptop totally wrecks the point of mobility. Unfortunately there is no other network drive method that I know off to which you can easily plug in usb drives.
If you want something cheap, grab a TC second hand off ebay. You can easily get by with a first generation model, assuming you are already using your airport for wireless.. The power supplies go, but this is a simple replacement.. open the TC and remove the internal supply.. power the board from a 5v plug pack.. at least 3A so you can use the USB with also a powered hub.. If you have some soldering ability you can build this for less than $100.. and it is very reliable once you replace the internal supply.
New TC is around US$300 for the cheaper 2TB model.
Thanks so much.
I won't be taking the risk of using an extrenal drive with Airport - seems like there's too many ways it can go wrong.
So it looks like getting Time Capsule is the answer.
I actually use my MacBook Pro as a desktop, and my MacBook Air as my mobile computer, so do actually have my 2 external drives going into that MacBook Pro daisy chanined via Firewire 800.
How would I make all my drives available to the network? I'm assuming from there that I can use Airport to backup anything on the network into TC?
One more question...can I have more than 1 TC connected, to allow for the fact that I have have nearly 6TB that I need to be able to backup? The largest TC I can see is 3TB.
Just look up how to share a drive to a network.. and then TM to it.
If you have 6TB to backup.. TC is not the right product.
Go to a Synology or QNAP NAS, 4 drive bay model. Load it with drives. That will give you TM, proper data raid, high speed and far better access.
You could juggle the system around so the existing 6TB is then used for backup of the NAS.. you still need a set of disks with original files and another set with the backup.. at least one.