well, to be honest, I don't quite now even yet how I would back up PS3 data.
Nor do I? And I don’t know if that's something "normal" users should have to know.
Anyway, I have also put Demon’s Soul on hold, I was 99% through the game, killed all Named Black Phantoms and all Bosses except the False King, I lost that fight whit him on 15%, because I fumbled around, and the fool drained me 6 levels, being level 140 I did not looked forward to grind for 6 hours just to regain the lost levels... I save that fore a rainy day, whit no new other games around.