Your backup tasks look just fine. Are you concerned about the
amount of time it has taken to back things up, and the amount of
data copied? The one thing that stands out is that you were
previously backing up a very limited amount of data (~10GB) from
your startup disk to a folder on the Drobo named "DESKTOP", but now
you're backing up most of your startup disk (~121GB) directly to
the root of the Drobo. This will definitely change how data is
arranged on the Drobo, and that will of course affect the
DroboBackup volume as well.
I'm also a bit confused about this statement:
I recently updated my Mac's OS
According to your log, you've been on 10.7.4 since late June.
Every task that has run indicates that you're still on 10.7.4.
Things look OK from my perspective, let me know how things are
working vs. how you expect it to be working.