monitor parameter (#564)

* monitor parameter

* Update 6.monitor-parameter.md

* Address metrics

* Update 6.monitor-parameter.md

docs-2.0/nebula-dashboard/6.monitor-parameter.md

@@ -0,0 +1,89 @@
+# Metrics
+
+This topic will describe the monitoring metrics in Nebula Graph Dashboard.
+
+!!! note
+
+    The default unit in **Disk** and **Network** is byte. The unit will change with the data magnitude as the page displays. For example, when the flow is less than 1 KB/s, the unit will be Bytes/s.
+
+## Machine
+
+### CPU
+
+|Parameter|Description|
+|:---|:---|
+|`cpu_utilization`| The percentage of used CPU. |
+|`cpu_idle`| The percentage of idled CPU. |
+|`cpu_wait`| The percentage of CPU waiting for IO operations. |
+|`cpu_user`| The percentage of CPU used by users. |
+|`cpu_system`| The percentage of CPU used by the system. |
+
+### Memory
+
+|Parameter| Description|
+|:---|:---|
+|`memory_utilization`| The percentage of used memory. |
+|`memory_used`| The memory space used (including caches). |
+|`memory_actual_used`| The memory space used (not including caches). |
+|`memory_free`| The memory space available. |
+
+### Load
+
+|Parameter| Description|
+|:---|:---|
+|`load_1m`| The average load of the system in the last 1 minute. |
+|`load_5m`| The average load of the system in the last 5 minutes. |
+|`load_15m`| The average load of the system in the last 15 minutes. |
+
+### Disk
+
+|Parameter| Description|
+|:---|:---|
+|`disk_used`| The disk space used. |
+|`disk_free`| The disk space available. |
+|`disk_readbytes`| The number of bytes that the system reads in the disk per second. |
+|`disk_writebytes`| The number of bytes that the system writes in the disk per second. |
+|`disk_readiops`| The number of read queries that the disk receives per second. |
+|`disk_writeiops`| The number of write queries that the disk receives per second. |
+|`inode_utilization`| The percentage of used inode. |
+
+### Network
+
+|Parameter| Description|
+|:---|:---|
+|`network_in_rate`| The number of bytes that the network card receives per second. |
+|`network_out_rate`| The number of bytes that the network card sends out per second. |
+|`network_in_errs`| The number of wrong bytes that the network card receives per second. |
+|`network_out_errs`| The number of wrong bytes that the network card sends out per second. |
+|`network_in_packets`| The number of data packages that the network card receives per second. |
+|`network_out_packets`| The number of data packages that the network card sends out per second. |
+
+## Service
+
+### Graph
+
+|Parameter| Description|
+|:---|:---|
+|`num_queries`| The number of queries. |
+|`num_slow_queries`| The number of slow queries. |
+|`query_latency_us`| The average latency of queries. |
+|`slow_query_latency_us`| The average latency of slow queries. |
+|`num_query_errors`| The number of queries in error. |
+
+### Meta
+
+|Parameter| Description|
+|:---|:---|
+|`heartbeat_latency_us`| The latency of heartbeats. |
+|`num_heartbeats`| The number of heartbeats. |
+
+### Storage
+
+|Parameter| Description|
+|:---|:---|
+|`add_edges_latency_us`| The average latency of adding edges. |
+|`add_vertices_latency_us`| The average latency of adding vertices. |
+|`delete_edges_latency_us`| The average latency of deleting edges. |
+|`delete_vertices_latency_us`| The average latency of deleting vertices. |
+|`forward_tranx_latency_us`| The average latency of transmitting. |
+|`get_neighbors_latency_us`| The average latency of querying neighbors. |