@Test
  public void testTwoIFFiles() throws Exception {
    diskProps.setPersistBackup(true);
    diskProps.setRegionName("testTwoIFFiles");
    diskProps.setDiskDirs(dirs);

    LocalRegion lr = (LocalRegion) DiskRegionHelperFactory.getSyncPersistOnlyRegion(cache,
        diskProps, Scope.LOCAL);
    DiskRegion dr = lr.getDiskRegion();
    assertEquals(null, dr.getMyInitializingID());
    PersistentMemberID myId = dr.getMyPersistentID();
    assertNotNull(myId);
    assertTrue(dr.getOnlineMembers().isEmpty());
    assertTrue(dr.getOfflineMembers().isEmpty());
    assertTrue(dr.getOfflineAndEqualMembers().isEmpty());

    // do recovery
    close(lr);
    assertEquals(true, (new File(dirs[0], "BACKUPtestTwoIFFiles.if")).exists());
    File extraIF = new File(dirs[1], "BACKUPtestTwoIFFiles.if");
    extraIF.createNewFile();
    try {
      lr = (LocalRegion) DiskRegionHelperFactory.getSyncPersistOnlyRegion(cache, diskProps,
          Scope.LOCAL);
      fail("expected IllegalStateException");
    } catch (IllegalStateException ignored) {
    } finally {
      extraIF.delete();
    }
  }
Make sure if we have multiple init file with the same ds name that ds creation fails. See bug
41883.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/DiskIFJUnitTest.java