private void saveCacheContent() {
    if (llapIo != null && savePath != null) {
      LlapDaemonProtocolProtos.CacheEntryList entryList = llapIo.fetchCachedContentInfo();
      if (!entryList.getEntriesList().isEmpty()) {
        try (OutputStream fos = new FileOutputStream(savePath)) {
          entryList.writeTo(fos);
          LOG.debug("Llap cache content info saved: " + savePath);
        } catch (IOException ex) {
          LOG.warn("Couldn't save llap cache content info.", ex);
        }
      }
    }
  }
Simple cache hydration strategy which saves the content info of the cache to a file on the local filesystem on
shutdown, and loads it when the daemon starts.
llap-server/src/java/org/apache/hadoop/hive/llap/cache/BasicLlapCacheHydration.java