private byte[] pmidToBytes(PersistentMemberID id) {
    try {
      HeapDataOutputStream hdos = new HeapDataOutputStream(KnownVersion.CURRENT);
      InternalDataSerializer.invokeToData(id, hdos);
      return hdos.toByteArray();
    } catch (IOException ex) {
      throw new DiskAccessException(
          String.format("Failed writing data to initialization file because: %s", ex),
          parent);
    }
  }
Write all live data to the init file
geode-core/src/main/java/org/apache/geode/internal/cache/DiskInitFile.java