public void start(final RpcScheduler rpcScheduler) throws IOException {
    if (!QuotaUtil.isQuotaEnabled(rsServices.getConfiguration())) {
      LOG.info("Quota support disabled");
      return;
    }

    LOG.info("Initializing RPC quota support");

    // Initialize quota cache
    quotaCache = new QuotaCache(rsServices);
    quotaCache.start();
    rpcThrottleEnabled = rpcThrottleStorage.isRpcThrottleEnabled();
    LOG.info("Start rpc quota manager and rpc throttle enabled is {}", rpcThrottleEnabled);
  }
Region Server Quota Manager. It is responsible to provide access to the quota information of each
user/table. The direct user of this class is the RegionServer that will get and check the
user/table quota for each operation (put, get, scan). For system tables and user/table with a
quota specified, the quota check will be a noop.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/RegionServerRpcQuotaManager.java