private void recordMutationWithoutWal(final Map<byte[], List<Cell>> familyMap) {
    numMutationsWithoutWAL.increment();
    if (numMutationsWithoutWAL.sum() <= 1) {
      LOG.info("writing data to region " + this
        + " with WAL disabled. Data may be lost in the event of a crash.");
    }

    long mutationSize = 0;
    for (List<Cell> cells : familyMap.values()) {
      // Optimization: 'foreach' loop is not used. See:
      // HBASE-12023 HRegion.applyFamilyMapToMemstore creates too many iterator objects
      assert cells instanceof RandomAccess;
      int listSize = cells.size();
      for (int i = 0; i < listSize; i++) {
        Cell cell = cells.get(i);
        mutationSize += cell.getSerializedSize();
      }
    }

    dataInMemoryWithoutWAL.add(mutationSize);
  }
Update LongAdders for number of puts without wal and the size of possible data loss. These
information are exposed by the region server metrics.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java