public static <K> Map<K, QuotaState> fetchGlobalQuotas(final String type,
    final Connection connection, final List<Get> gets, final KeyFromRow<K> kfr) throws IOException {
    long nowTs = EnvironmentEdgeManager.currentTime();
    Result[] results = doGet(connection, gets);

    Map<K, QuotaState> globalQuotas = new HashMap<>(results.length);
    for (int i = 0; i < results.length; ++i) {
      byte[] row = gets.get(i).getRow();
      K key = kfr.getKeyFromRow(row);

      QuotaState quotaInfo = new QuotaState(nowTs);
      globalQuotas.put(key, quotaInfo);

      if (results[i].isEmpty()) continue;
      assert Bytes.equals(row, results[i].getRow());

      byte[] data = results[i].getValue(QUOTA_FAMILY_INFO, QUOTA_QUALIFIER_SETTINGS);
      if (data == null) continue;

      try {
        Quotas quotas = quotasFromData(data);
        quotas = updateClusterQuotaToMachineQuota(quotas, kfr.getFactor(key));
        quotaInfo.setQuotas(quotas);
      } catch (IOException e) {
        LOG.error("Unable to parse " + type + " '" + key + "' quotas", e);
        globalQuotas.remove(key);
      }
    }
    return globalQuotas;
  }
Returns true if the support for quota is enabled
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/QuotaUtil.java