private void completeBackup(DiskStoreImpl diskStore, DiskStoreBackup backup) throws IOException {
    if (backup == null) {
      return;
    }
    try {
      // Wait for oplogs to be unpreblown before backing them up.
      diskStore.waitForDelayedWrites();

      // Backup all of the oplogs
      for (Oplog oplog : backup.getPendingBackup()) {
        if (isCancelled()) {
          break;
        }
        oplog.finishKrf();
        fileCopier.copyOplog(diskStore, oplog);

        // Allow the oplog to be deleted, and process any pending delete
        backup.backupFinished(oplog);
      }
    } finally {
      backup.cleanup();
    }
  }
Copy the oplogs to the backup directory. This is the final step of the backup process. The
oplogs we copy are defined in the startDiskStoreBackup method.
geode-core/src/main/java/org/apache/geode/internal/cache/backup/BackupTask.java