I think this has been mentioned in passing, but I will bring it up again in more detail. Based on my experience it is easiest to have a 2nd internal HD. For the Sony model you mentioned a HD drive caddy is available, it replaces the DVD drive. This is what I have in both my notebooks (Dell and Lenovo), it works great and lasts a long time. I would keep the HD size to 750GB or less since the 1TB drives are thick and may not fit. Then you could just make a clone of your HD and you now have a spare boot drive. Yes, you would have to buy a 2.5 HD but when you do you get the cloning software. I would also keep the drive RPM at 5400 since 7200 can generate heat.

Here is what I did.
Step 1) Install HD into drive caddy
Step 2) Remove DVD drive from PC (please note these are usually hot swappable, but I do not own a Sony)
Step 3) Slide in drive caddy with HD installed
Step 4) Wait for the drivers to load
Step 5) Install drive cloning software (I like Seagate drives and software)
Step 6) Clone the entire HD (all partitions)
Step 7 Have fun you now have a exact copy of your boot drive
Step 8) Rinse and repeat step 6 as necessary.

Or after step 6 is complete just copy your data directory over to the 2nd hard drive on a scheduled basis (this is what I actually do). And if a long time has passed or you have made major changes repeat step 6 above.

I am also pasting a link to the drive caddy from some vendor. I am not endorsing this vendor or caddy just showing how easy they are to find.

http://www.batterystyle.com/sony-vpc...-p-433506.html