Ignore user input for elastic pool's StorageMB and recalculate based on Dtu and coefficient of the edition

Author: hungmai-msft

src/ResourceManager/Sql/Commands.Sql/ServerUpgrade/Cmdlet/StartAzureSqlServerUpgrade.cs

@@ -53,6 +53,10 @@ public class StartAzureSqlServerUpgrade : AzureSqlServerUpgradeCmdletBase<AzureS
             HelpMessage = "Determines the collection of recommended elastic pool properties for server upgrade")]
         public UpgradeRecommendedElasticPoolProperties[] ElasticPoolCollection { get; set; }
 
+        private const int StorageMbPerDtuBasic = 100;
+        private const int StorageMbPerDtuStandard = 1024;
+        private const int StorageMbPerDtuPremium = 512;
+
         /// <summary>
         /// Check to see if the server already exists in this resource group.
         /// </summary>
@@ -82,6 +86,26 @@ public class StartAzureSqlServerUpgrade : AzureSqlServerUpgradeCmdletBase<AzureS
         /// <returns>The generated model from user input</returns>
         protected override IEnumerable<AzureSqlServerUpgradeStartModel> ApplyUserInputToModel(IEnumerable<AzureSqlServerUpgradeStartModel> models)
         {
+            // Ignore user input and recalculate StorageMb based on Dtu and coefficient of the edition
+            foreach (var elasticPoolProperties in ElasticPoolCollection)
+            {
+                switch (elasticPoolProperties.Edition.ToLower())
+                {
+                    case "basic":
+                        elasticPoolProperties.StorageMb = elasticPoolProperties.Dtu*StorageMbPerDtuBasic;
+                        break;
+                    case "standard":
+                        elasticPoolProperties.StorageMb = elasticPoolProperties.Dtu * StorageMbPerDtuStandard;
+                        break;
+                    case "premium":
+                        elasticPoolProperties.StorageMb = elasticPoolProperties.Dtu * StorageMbPerDtuPremium;
+                        break;
+                    default:
+                        throw new PSArgumentException(string.Format("Edition {0} is invalid", elasticPoolProperties.Edition));
+                }
+                    
+            }
+
             var newEntity = new List<AzureSqlServerUpgradeStartModel>();
             newEntity.Add(new AzureSqlServerUpgradeStartModel
             {