I work in particle astrophysics data processing and management, mostly with gamma ray events for Fermi gamma ray space-telescope. Our total data size after five years is somewhere around 2 PB, but the data set usually used for analysis runs about 200 TB, not really that large. AFAIK, none of the 100+ collaborators use Hadoop. Mostly they use software I develop to run batch jobs in parallel on one of several clusters.
LSST, which I also am starting to work on, will be different, as the raw data alone will approach 4TB a day.