@Override
  protected final void postSetUp() throws Exception {
    diskProps.setDiskDirs(dirs);
    diskProps.setTimeInterval(1000l);
    diskProps.setBytesThreshold(10000l);
    diskProps.setOverFlowCapacity(1000);
    region = DiskRegionHelperFactory.getAsyncOverFlowOnlyRegion(cache, diskProps);
    log = ds.getLogWriter();
  }
Do not change the value OP_COUNT = 400 The test case is dependent on this value.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/diskPerf/DiskRegOverflowAsyncJUnitPerformanceTest.java