optimize logs of io manager (#102)

deps/oblib/src/lib/io/ob_io_common.cpp

@@ -403,7 +403,7 @@ int ObIOChannel::init(const int32_t queue_depth)
     MEMSET(&context_, 0, sizeof(context_));
     if (0 != (io_ret = ob_io_setup(MAX_AIO_EVENT_CNT, &context_))) {
       ret = OB_IO_ERROR;
-      COMMON_LOG(ERROR, "Fail to setup io context, ", K(ret), K(io_ret));
+      COMMON_LOG(ERROR, "Fail to setup io context, check config aio-max-nr of operating system", K(ret), K(io_ret));
     } else {
       submit_cnt_ = 0;
       can_submit_request_ = true;

src/observer/ob_server.cpp

@@ -1059,7 +1059,7 @@ int ObServer::init_io()
       } else {
         // allow load benchmark fail
         if (OB_FAIL(ObIOBenchmark::get_instance().init("etc"))) {
-          LOG_ERROR("init io benchmark fail, ", K(ret));
+          LOG_WARN("init io benchmark fail, ", K(ret));
         }
         ret = OB_SUCCESS;
       }