Backing up HDDs on a complex setup?

[superspiffy]

My setup:
I have two 250 GB externals, daisy chained and connected to my MBP via FireWire 800. I have all my photos, movies, music on those drives and everything is just nice and dandy.

What I want to do:
I want to get a 1 TB external hdd, plug it to my router, and use it to backup those two 250 GB externals. But I want every change I make to those two 250 GB externals to get copied over to the 1 TB automatically, but I don't want changes on the 1 TB to be carried over to the two 250 GBs. So in short, I don't just want to back up the two 250 GBs to the 1 TB, I want to mirror them, but only in one direction.

I'd also want to open up the router to the Internet, allowing me to access all my files on whatever network I happen to be at, so I can finally stop bringing the two 250 GB externals wherever I go.

Why do I want this setup?
Because I want my data to be on two physical hdds at the same time. This provides good redundancy in case one or the other drive stops working and I lose all my irreplaceable files and I also want to be able to access my files on the backup drive through the Internet.

So is there a way I can do this via Automator or any other programs?

[blodwyn]

My setup:
What I want to do:
I want to get a 1 TB external hdd, plug it to my router, and use it to backup those two 250 GB externals. But I want every change I make to those two 250 GB externals to get copied over to the 1 TB automatically, but I don't want changes on the 1 TB to be carried over to the two 250 GBs. So in short, I don't just want to back up the two 250 GBs to the 1 TB, I want to mirror them, but only in one direction.

So is there a way I can do this via Automator or any other programs?

'Automatically' might be tricky if you mean you want it to happen in real time. If you don't mind it happening on a schedule, then Chronosync (http://www.econtechnologies.com/site/Pages/ChronoSync/chrono_overview.html) could be your answer. You can set it to sync in one direction only which suits what you want, and you can set a schedule to make it happen at whatever time periods suit you. You could also do the same with SuperDuper.

[CarlsonCustoms]

Can't you use the Rsync command and then make an automater script and have that script run automatically with ical? I know this can be done but don't know the specifics. I want to do this same thing actually with my nas box but havent' found the right commands yet.

Zack

[betelgeuse1]

I'm not sure how urgent your need is, but there is a good chance that Time Machine in Leopard will do what you want. However, I've not worked with the betas, and am not sure how Time Machine deals with external drives. Also, my understanding is that the volume selected as the Time Machine backup cannot be used for anything else (not sure if that applies to physical drives or just partitions.)