message: update log level
diff: @@ -6,10 +6,10 @@ Nebula uses [glog](https://github.com/google/glog) to print logs, gflag to contr
  ### Two most commonly used flags in glog
  -- minloglevel 0-4: the numbers of severity levels INFO, WARNING, ERROR, and FATAL are 0, 1, 2, and 3, respectively. Usually specified as 0 in debug, 1 in production.
  -- v 0-4: when minloglevel is set to 0, you can further set the severity level of the debug log. The larger the value, the more detailed.
  +- minloglevel 0-3: the numbers of severity levels INFO(DEBUG), WARNING, ERROR, and FATAL are 0, 1, 2, and 3, respectively. Usually specified as 0 in debug, 1 in production. If you set the minloglevel to 4, no logs are printed.
  +- v 0-4: when minloglevel is set to 0, you can further set the severity level of the debug log. The larger the value, the more detailed the log.
  -### Config Files
  +### Configuration Files
  The default severity level for the metad, graphd, storaged logs can be found in the configuration files (usually under `/usr/local/nebula/etc/`).
  @@ -21,9 +21,9 @@ Check all the flag values (log values included) of the current glags with the fo
  > curl ${ws_ip}:${ws_port}/get_flags
  ```
  -Descriptions:
  +Parameters:
  -- `ws_ip` is the HTTP service ip, which can be found in the above config files (default is 127.0.0.1)
  +- `ws_ip` is the HTTP service IP, which can be found in the above configuration files (default IP is 127.0.0.1)
  - `ws_port` is the HTTP port, the default value for `metad` is 11000, `storaged` is 12000 and `graphd` is 13000
  For example, check the severity minloglevel of storaged:
  @@ -39,6 +39,15 @@ Change the logs severity level to **most detailed** with the following command.
  > curl "http://127.0.0.1:12000/set_flags?flag=minloglevel&value=0"
  ```
  +In Nebula console, check the severity minloglevel of graphd and set it to **most detailed** with the following commands.
  +
  +```ngql
  +nebula> GET CONFIGS graph:minloglevel
  +nebula> UPDATE CONFIGS graph:minloglevel=0
  +```
  +
  +To change the severity of the storage log, replace `graph` in the above command with `storage`. Note that nebula only supports modifying the graph and storage log severity via console, meta log cannot be changed.
  +
  Or **close** all logs print (FATAL only).
  ```bash
  