backing up an external hard drive with TM

[4now]

Is it possible to add an external drive to be backed up by Time Machine.

For example:
I have a MacBook Pro & will have two external Hard drives.

I want to use one external HD for storage only (since space is limited on my MBP)

then a second external HD for Time Machine to backup the files from both the MBP and the Storage HD.

that way everything is copied at least once.

[cdarlington1]

You can...in the time machine preference pane, you can customize exactly what gets backed up so you can have your MBP internal drive and 1 external drive back up to the other external drive. One thing to keep in mind, is you will want the drive that is going to be backing up everything to be the same or larger in terms of space...that way it can keep more copies of backups...say you have an internal 160gb and a external drive (for video or music or movies, etc...) and it's 500gb. I would recommend a 750gb external for Time Machine...hope this makes sense (long day at work today...).

[4now]

o yeah that makes sense

thats how I was thinking

thanks so much

[4now]

I don't see an option to add an external drive to what is being backed up.

It only appears to allow you to 'exclude' items