private void flush(final HRegion r, final HRegionServer server) throws IOException {
    LOG.info("Flush " + r.toString() + " on " + server.getServerName() + ", " + r.flush(true)
      + ", size=" + server.getRegionServerAccounting().getGlobalMemStoreDataSize());
  }
Flush and log stats on flush
hbase-server/src/test/java/org/apache/hadoop/hbase/TestGlobalMemStoreSize.java