Another way to look at it would be going the other way smaller - nanotechnology - check out articles by Eric Drexler on the net. Tracking billions and billons of 'nano machines' produced by molecular production lines might require exabytes to track 'em....

>>Current estimates of numbers of stars in the galaxy are around 200 billion, so around 80Gb per star in the galaxy.
>
>Done it again, 3 extra zeroes this time - that should be 80Mb