Enhancement of README.md for the vSphere input plugin. (#4788)

plugins/inputs/vsphere/README.md

@@ -5,13 +5,16 @@ The VMware vSphere plugin uses the vSphere API to gather metrics from multiple v
 * Clusters
 * Hosts
 * VMs
-* Data stores
+* Datastores
 
 ## Configuration
 
 NOTE: To disable collection of a specific resource type, simply exclude all metrics using the XX_metric_exclude. 
 For example, to disable collection of VMs, add this:
-```vm_metric_exclude = [ "*" ]```
+
+```
+vm_metric_exclude = [ "*" ]
+```
 
 ```
 # Read metrics from one or many vCenters
@@ -168,9 +171,16 @@ For example, to disable collection of VMs, add this:
 
 ### Objects and Metrics Per Query
 
-Default settings for vCenter 6.5 and above is 256. Prior versions of vCenter have this set to 64. A vCenter administrator
+By default, in vCenter's configuration a limit is set to the number of entities that are included in a performance chart query. Default settings for vCenter 6.5 and above is 256. Prior versions of vCenter have this set to 64. 
-can change this setting, which should be reflected in this plugin. See this [VMware KB article](https://kb.vmware.com/s/article/2107096)
+A vCenter administrator can change this setting, see this [VMware KB article](https://kb.vmware.com/s/article/2107096) for more information.
-for more information.
+
+Any modification should be reflected in this plugin by modifying the parameter `max_query_objects`
+
+```
+  ## number of objects to retreive per query for realtime resources (vms and hosts)
+  ## set to 64 for vCenter 5.5 and 6.0 (default: 256)
+  # max_query_objects = 256
+```
 
 ### Collection and Discovery concurrency
 
@@ -178,6 +188,14 @@ On large vCenter setups it may be prudent to have multiple concurrent go routine
 in order to avoid potential errors for time elapsed during a collection cycle. This should never be greater than 8,
 though the default of 1 (no concurrency) should be sufficient for most configurations.
 
+For setting up concurrency, modify `collect_concurrency` and `discover_concurrency` parameters.
+
+```
+  ## number of go routines to use for collection and discovery of objects and metrics
+  # collect_concurrency = 1
+  # discover_concurrency = 1
+```
+
 ## Measurements & Fields
 
 - Cluster Stats