private long setBackupFiles(final File dir) throws IOException {
    File dir1 = new File(dir, "test1");
    File dir2 = new File(dir1, "test2");
    dir2.mkdirs();

    File textFile = new File(dir2, "my.txt");
    Files.createFile(textFile.toPath());

    List<File> backupList = new ArrayList<>();
    backupList.add(dir2);
    getCache().setBackupFiles(backupList);

    return textFile.lastModified();
  }
Test what happens when we restart persistent members while there is an accessor concurrently
performing puts.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/backup/BackupDistributedTest.java