private void deleteOldUserFile(final File dir) throws IOException {
    File userDir = new File(dir, "userbackup-");
    FileUtils.deleteDirectory(userDir);
  }
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