Portal 2 on the PS3 does not require a hard drive install
Hard driver installation is common these days with every major game opting for an irritating 20 minute or so installation time. Fortunately PlayStation3 owners who are picking up a copy of Portal 2 next week wont have any installation to face.
Portal 2’s Project Lead Joshua Weier has confirmed this:
We do not require users to install to the hard drive [note: there’s no hard drive install at all], but you’ll need 22 MB for saved games.
Portal 2 releases next week for the PS3, Xbox 360 and PC. Stay tuned with GB for more news and updates.