add property copy array example

Author: tfitzmac

articles/azure-resource-manager/templates/copy-properties.md

@@ -2,7 +2,7 @@
 title: Define multiple instances of a property
 description: Use copy operation in an Azure Resource Manager template to iterate multiple times when creating a property on a resource.
 ms.topic: conceptual
-ms.date: 04/08/2020
+ms.date: 04/14/2020
 ---
 # Property iteration in ARM templates
 
@@ -107,7 +107,63 @@ Resource Manager expands the `copy` array during deployment. The name of the arr
 
 The copy operation is helpful when working with arrays because you can iterate through each element in the array. Use the `length` function on the array to specify the count for iterations, and `copyIndex` to retrieve the current index in the array.
 
+The following example template creates a failover group for databases that are passed in as an array.
 
+```json
+{
+    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
+    "contentVersion": "1.0.0.0",
+    "parameters": {
+        "primaryServerName": {
+            "type": "string"
+        },
+        "secondaryServerName": {
+            "type": "string"
+        },
+        "databaseNames": {
+            "type": "array",
+            "defaultValue": [
+                "mydb1",
+                "mydb2",
+                "mydb3"
+            ]
+        }
+    },
+    "variables": {
+        "failoverName": "[concat(parameters('primaryServerName'),'/', parameters('primaryServerName'),'failovergroups')]"
+    },
+    "resources": [
+        {
+            "type": "Microsoft.Sql/servers/failoverGroups",
+            "apiVersion": "2015-05-01-preview",
+            "name": "[variables('failoverName')]",
+            "properties": {
+                "readWriteEndpoint": {
+                    "failoverPolicy": "Automatic",
+                    "failoverWithDataLossGracePeriodMinutes": 60
+                },
+                "readOnlyEndpoint": {
+                    "failoverPolicy": "Disabled"
+                },
+                "partnerServers": [
+                    {
+                        "id": "[resourceId('Microsoft.Sql/servers', parameters('secondaryServerName'))]"
+                    }
+                ],
+                "copy": [
+                    {
+                        "name": "databases",
+                        "count": "[length(parameters('databaseNames'))]",
+                        "input": "[resourceId('Microsoft.Sql/servers/databases', parameters('primaryServerName'), parameters('databaseNames')[copyIndex('databases')])]"
+                    }
+                ]
+            }
+        }
+    ],
+    "outputs": {
+    }
+}
+```
 
 The copy element is an array so you can specify more than one property for the resource.