Also near the bottom.

  > On the database side, I configured VoltDB to run at K=0,
  > which means the database was running with HA switched off.
  > Most applications would not run that way in a production
  > environment, but my goal was to test client-side throughput
  > and scaling; I wasn’t really focused the database side of
  > the tests.

Testament to the author for mentioning it. It makes me interested in voltdb, whereas before it was unknown to me. But the numbers should indeed be taken with a grain of salt I think.