private void backupDir(int vmId) throws IOException {
    File diskDir = getDiskDir(vmId);
    File backupDir = new File(rootDir, diskDir.getName() + ".bk");

    copyDirectory(diskDir, backupDir);
  }
Tests to make sure that after we get a conflicting persistent data exception, we can still
recover.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/persistence/PersistentRecoveryOrderDUnitTest.java