private void deleteOutdatedFiles() {
    // Normally, only need to delete the expired file once. When the WAL disk file size exceeds the
    // threshold, the system continues to delete expired files until the disk size is smaller than
    // the threshold.
    boolean firstLoop = true;
    while ((firstLoop || shouldThrottle()) && !Thread.interrupted()) {
      deleteOutdatedFilesInWALNodes();
      if (firstLoop && shouldThrottle()) {
        logger.warn(
            "WAL disk usage {} is larger than the wal_throttle_threshold_in_byte * 0.8 {}, please check your write load, iot consensus and the pipe module. It's better to allocate more disk for WAL.",
            getTotalDiskUsage(),
            getThrottleThreshold());
      }
      firstLoop = false;
    }
  }
Reboot wal delete thread to hot modify delete wal period.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/WALManager.java