private Region createRegion(String regionName) {
    if (cache.findDiskStore("store") == null) {
      cache.createDiskStoreFactory().setMaxOplogSize(1).setDiskDirs(dirs).create("store");
    }
    Region region = cache.createRegionFactory().setDiskStoreName("store")
        .setDataPolicy(DataPolicy.PERSISTENT_REPLICATE).create(regionName);
    return region;
  }
Validate that values are, or are not, in memory
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/DiskRegionAsyncRecoveryJUnitTest.java