diff --git a/clients/client-cost-optimization-hub/src/commands/GetRecommendationCommand.ts b/clients/client-cost-optimization-hub/src/commands/GetRecommendationCommand.ts
index a28819a2fc91..d72189dd0f80 100644
--- a/clients/client-cost-optimization-hub/src/commands/GetRecommendationCommand.ts
+++ b/clients/client-cost-optimization-hub/src/commands/GetRecommendationCommand.ts
@@ -58,8 +58,8 @@ export interface GetRecommendationCommandOutput extends GetRecommendationRespons
  * //   costCalculationLookbackPeriodInDays: Number("int"),
  * //   estimatedSavingsPercentage: Number("double"),
  * //   estimatedSavingsOverCostCalculationLookbackPeriod: Number("double"),
- * //   currentResourceType: "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances",
- * //   recommendedResourceType: "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances",
+ * //   currentResourceType: "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances" || "RdsDbInstanceStorage" || "RdsDbInstance",
+ * //   recommendedResourceType: "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances" || "RdsDbInstanceStorage" || "RdsDbInstance",
  * //   region: "STRING_VALUE",
  * //   source: "ComputeOptimizer" || "CostExplorer",
  * //   lastRefreshTimestamp: new Date("TIMESTAMP"),
@@ -403,6 +403,23 @@ export interface GetRecommendationCommandOutput extends GetRecommendationRespons
  * //         },
  * //       },
  * //     },
+ * //     rdsDbInstance: { // RdsDbInstance
+ * //       configuration: { // RdsDbInstanceConfiguration
+ * //         instance: { // DbInstanceConfiguration
+ * //           dbInstanceClass: "STRING_VALUE",
+ * //         },
+ * //       },
+ * //       costCalculation: "<ResourceCostCalculation>",
+ * //     },
+ * //     rdsDbInstanceStorage: { // RdsDbInstanceStorage
+ * //       configuration: { // RdsDbInstanceStorageConfiguration
+ * //         storageType: "STRING_VALUE",
+ * //         allocatedStorageInGb: Number("double"),
+ * //         iops: Number("double"),
+ * //         storageThroughput: Number("double"),
+ * //       },
+ * //       costCalculation: "<ResourceCostCalculation>",
+ * //     },
  * //   },
  * //   recommendedResourceDetails: {//  Union: only one key present
  * //     lambdaFunction: {
@@ -596,6 +613,23 @@ export interface GetRecommendationCommandOutput extends GetRecommendationRespons
  * //       },
  * //       costCalculation: "<SavingsPlansCostCalculation>",
  * //     },
+ * //     rdsDbInstance: {
+ * //       configuration: {
+ * //         instance: {
+ * //           dbInstanceClass: "STRING_VALUE",
+ * //         },
+ * //       },
+ * //       costCalculation: "<ResourceCostCalculation>",
+ * //     },
+ * //     rdsDbInstanceStorage: {
+ * //       configuration: {
+ * //         storageType: "STRING_VALUE",
+ * //         allocatedStorageInGb: Number("double"),
+ * //         iops: Number("double"),
+ * //         storageThroughput: Number("double"),
+ * //       },
+ * //       costCalculation: "<ResourceCostCalculation>",
+ * //     },
  * //   },
  * //   tags: [ // TagList
  * //     { // Tag
diff --git a/clients/client-cost-optimization-hub/src/commands/ListRecommendationSummariesCommand.ts b/clients/client-cost-optimization-hub/src/commands/ListRecommendationSummariesCommand.ts
index b082cd138cae..700ce1828778 100644
--- a/clients/client-cost-optimization-hub/src/commands/ListRecommendationSummariesCommand.ts
+++ b/clients/client-cost-optimization-hub/src/commands/ListRecommendationSummariesCommand.ts
@@ -60,7 +60,7 @@ export interface ListRecommendationSummariesCommandOutput
  *       "STRING_VALUE",
  *     ],
  *     resourceTypes: [ // ResourceTypeList
- *       "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances",
+ *       "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances" || "RdsDbInstanceStorage" || "RdsDbInstance",
  *     ],
  *     actionTypes: [ // ActionTypeList
  *       "Rightsize" || "Stop" || "Upgrade" || "PurchaseSavingsPlans" || "PurchaseReservedInstances" || "MigrateToGraviton",
diff --git a/clients/client-cost-optimization-hub/src/commands/ListRecommendationsCommand.ts b/clients/client-cost-optimization-hub/src/commands/ListRecommendationsCommand.ts
index 4160b1094229..e79567e62a04 100644
--- a/clients/client-cost-optimization-hub/src/commands/ListRecommendationsCommand.ts
+++ b/clients/client-cost-optimization-hub/src/commands/ListRecommendationsCommand.ts
@@ -53,7 +53,7 @@ export interface ListRecommendationsCommandOutput extends ListRecommendationsRes
  *       "STRING_VALUE",
  *     ],
  *     resourceTypes: [ // ResourceTypeList
- *       "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances",
+ *       "Ec2Instance" || "LambdaFunction" || "EbsVolume" || "EcsService" || "Ec2AutoScalingGroup" || "Ec2InstanceSavingsPlans" || "ComputeSavingsPlans" || "SageMakerSavingsPlans" || "Ec2ReservedInstances" || "RdsReservedInstances" || "OpenSearchReservedInstances" || "RedshiftReservedInstances" || "ElastiCacheReservedInstances" || "RdsDbInstanceStorage" || "RdsDbInstance",
  *     ],
  *     actionTypes: [ // ActionTypeList
  *       "Rightsize" || "Stop" || "Upgrade" || "PurchaseSavingsPlans" || "PurchaseReservedInstances" || "MigrateToGraviton",
diff --git a/clients/client-cost-optimization-hub/src/models/models_0.ts b/clients/client-cost-optimization-hub/src/models/models_0.ts
index 6f719c09611d..bb8167a31ade 100644
--- a/clients/client-cost-optimization-hub/src/models/models_0.ts
+++ b/clients/client-cost-optimization-hub/src/models/models_0.ts
@@ -1136,6 +1136,97 @@ export interface OpenSearchReservedInstances {
   costCalculation?: ReservedInstancesCostCalculation;
 }
 
+/**
+ * <p>The DB instance configuration used for recommendations.</p>
+ * @public
+ */
+export interface DbInstanceConfiguration {
+  /**
+   * <p>The DB instance class of the DB instance.</p>
+   * @public
+   */
+  dbInstanceClass?: string;
+}
+
+/**
+ * <p>The Amazon RDS DB instance configuration used for recommendations.</p>
+ * @public
+ */
+export interface RdsDbInstanceConfiguration {
+  /**
+   * <p>Details about the instance configuration.</p>
+   * @public
+   */
+  instance?: DbInstanceConfiguration;
+}
+
+/**
+ * <p>Contains the details of an Amazon RDS DB instance.</p>
+ * @public
+ */
+export interface RdsDbInstance {
+  /**
+   * <p>The Amazon RDS DB instance configuration used for recommendations.</p>
+   * @public
+   */
+  configuration?: RdsDbInstanceConfiguration;
+
+  /**
+   * <p>Cost impact of the resource recommendation.</p>
+   * @public
+   */
+  costCalculation?: ResourceCostCalculation;
+}
+
+/**
+ * <p>The Amazon RDS DB instance storage configuration used for recommendations.</p>
+ * @public
+ */
+export interface RdsDbInstanceStorageConfiguration {
+  /**
+   * <p>The storage type to associate with the DB instance.</p>
+   * @public
+   */
+  storageType?: string;
+
+  /**
+   * <p>The new amount of storage in GB to allocate for the DB instance.</p>
+   * @public
+   */
+  allocatedStorageInGb?: number;
+
+  /**
+   * <p>The amount of Provisioned IOPS (input/output operations per second) to be initially
+   *       allocated for the DB instance.</p>
+   * @public
+   */
+  iops?: number;
+
+  /**
+   * <p>The storage throughput for the DB instance.</p>
+   * @public
+   */
+  storageThroughput?: number;
+}
+
+/**
+ * <p>Contains the details of an Amazon RDS DB instance storage.</p>
+ * @public
+ */
+export interface RdsDbInstanceStorage {
+  /**
+   * <p>The Amazon RDS DB instance storage configuration used for recommendations.</p>
+   * @public
+   */
+  configuration?: RdsDbInstanceStorageConfiguration;
+
+  /**
+   * <p>Cost impact of the resource recommendation.</p>
+   * @public
+   */
+  costCalculation?: ResourceCostCalculation;
+}
+
 /**
  * <p>The RDS reserved instances configuration used for recommendations.</p>
  * @public
@@ -1430,6 +1521,8 @@ export type ResourceDetails =
   | ResourceDetails.ElastiCacheReservedInstancesMember
   | ResourceDetails.LambdaFunctionMember
   | ResourceDetails.OpenSearchReservedInstancesMember
+  | ResourceDetails.RdsDbInstanceMember
+  | ResourceDetails.RdsDbInstanceStorageMember
   | ResourceDetails.RdsReservedInstancesMember
   | ResourceDetails.RedshiftReservedInstancesMember
   | ResourceDetails.SageMakerSavingsPlansMember
@@ -1457,6 +1550,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1478,6 +1573,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1499,6 +1596,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1520,6 +1619,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1541,6 +1642,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1562,6 +1665,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1583,6 +1688,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1604,6 +1711,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1625,6 +1734,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1646,6 +1757,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1667,6 +1780,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans: Ec2InstanceSavingsPlans;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1688,6 +1803,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans: ComputeSavingsPlans;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown?: never;
   }
 
@@ -1709,6 +1826,54 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans: SageMakerSavingsPlans;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
+    $unknown?: never;
+  }
+
+  /**
+   * <p>The DB instance recommendation details.</p>
+   * @public
+   */
+  export interface RdsDbInstanceMember {
+    lambdaFunction?: never;
+    ecsService?: never;
+    ec2Instance?: never;
+    ebsVolume?: never;
+    ec2AutoScalingGroup?: never;
+    ec2ReservedInstances?: never;
+    rdsReservedInstances?: never;
+    elastiCacheReservedInstances?: never;
+    openSearchReservedInstances?: never;
+    redshiftReservedInstances?: never;
+    ec2InstanceSavingsPlans?: never;
+    computeSavingsPlans?: never;
+    sageMakerSavingsPlans?: never;
+    rdsDbInstance: RdsDbInstance;
+    rdsDbInstanceStorage?: never;
+    $unknown?: never;
+  }
+
+  /**
+   * <p>The DB instance storage recommendation details.</p>
+   * @public
+   */
+  export interface RdsDbInstanceStorageMember {
+    lambdaFunction?: never;
+    ecsService?: never;
+    ec2Instance?: never;
+    ebsVolume?: never;
+    ec2AutoScalingGroup?: never;
+    ec2ReservedInstances?: never;
+    rdsReservedInstances?: never;
+    elastiCacheReservedInstances?: never;
+    openSearchReservedInstances?: never;
+    redshiftReservedInstances?: never;
+    ec2InstanceSavingsPlans?: never;
+    computeSavingsPlans?: never;
+    sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage: RdsDbInstanceStorage;
     $unknown?: never;
   }
 
@@ -1729,6 +1894,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans?: never;
     computeSavingsPlans?: never;
     sageMakerSavingsPlans?: never;
+    rdsDbInstance?: never;
+    rdsDbInstanceStorage?: never;
     $unknown: [string, any];
   }
 
@@ -1746,6 +1913,8 @@ export namespace ResourceDetails {
     ec2InstanceSavingsPlans: (value: Ec2InstanceSavingsPlans) => T;
     computeSavingsPlans: (value: ComputeSavingsPlans) => T;
     sageMakerSavingsPlans: (value: SageMakerSavingsPlans) => T;
+    rdsDbInstance: (value: RdsDbInstance) => T;
+    rdsDbInstanceStorage: (value: RdsDbInstanceStorage) => T;
     _: (name: string, value: any) => T;
   }
 
@@ -1767,6 +1936,8 @@ export namespace ResourceDetails {
       return visitor.ec2InstanceSavingsPlans(value.ec2InstanceSavingsPlans);
     if (value.computeSavingsPlans !== undefined) return visitor.computeSavingsPlans(value.computeSavingsPlans);
     if (value.sageMakerSavingsPlans !== undefined) return visitor.sageMakerSavingsPlans(value.sageMakerSavingsPlans);
+    if (value.rdsDbInstance !== undefined) return visitor.rdsDbInstance(value.rdsDbInstance);
+    if (value.rdsDbInstanceStorage !== undefined) return visitor.rdsDbInstanceStorage(value.rdsDbInstanceStorage);
     return visitor._(value.$unknown[0], value.$unknown[1]);
   };
 }
@@ -1786,6 +1957,8 @@ export const ResourceType = {
   ELASTI_CACHE_RESERVED_INSTANCES: "ElastiCacheReservedInstances",
   LAMBDA_FUNCTION: "LambdaFunction",
   OPEN_SEARCH_RESERVED_INSTANCES: "OpenSearchReservedInstances",
+  RDS_DB_INSTANCE: "RdsDbInstance",
+  RDS_DB_INSTANCE_STORAGE: "RdsDbInstanceStorage",
   RDS_RESERVED_INSTANCES: "RdsReservedInstances",
   REDSHIFT_RESERVED_INSTANCES: "RedshiftReservedInstances",
   SAGE_MAKER_SAVINGS_PLANS: "SageMakerSavingsPlans",
@@ -1943,7 +2116,7 @@ export interface GetRecommendationResponse {
   estimatedMonthlySavings?: number;
 
   /**
-   * <p>The estimated monthly cost of the recommendation.</p>
+   * <p>The estimated monthly cost of the current resource. For Reserved Instances and Savings Plans, it refers to the cost for eligible usage.</p>
    * @public
    */
   estimatedMonthlyCost?: number;
@@ -2274,7 +2447,7 @@ export interface Recommendation {
   estimatedSavingsPercentage?: number;
 
   /**
-   * <p>The estimated monthly cost for the recommendation.</p>
+   * <p>The estimated monthly cost of the current resource. For Reserved Instances and Savings Plans, it refers to the cost for eligible usage.</p>
    * @public
    */
   estimatedMonthlyCost?: number;
diff --git a/clients/client-cost-optimization-hub/src/protocols/Aws_json1_0.ts b/clients/client-cost-optimization-hub/src/protocols/Aws_json1_0.ts
index 2950834b7d85..b93e4a365bf3 100644
--- a/clients/client-cost-optimization-hub/src/protocols/Aws_json1_0.ts
+++ b/clients/client-cost-optimization-hub/src/protocols/Aws_json1_0.ts
@@ -80,6 +80,9 @@ import {
   ListRecommendationSummariesResponse,
   OpenSearchReservedInstances,
   OrderBy,
+  RdsDbInstance,
+  RdsDbInstanceStorage,
+  RdsDbInstanceStorageConfiguration,
   RdsReservedInstances,
   Recommendation,
   RecommendationSummary,
@@ -544,6 +547,8 @@ const de_ComputeSavingsPlans = (output: any, context: __SerdeContext): ComputeSa
 
 // de_ComputeSavingsPlansConfiguration omitted.
 
+// de_DbInstanceConfiguration omitted.
+
 /**
  * deserializeAws_json1_0EbsVolume
  */
@@ -760,6 +765,43 @@ const de_OpenSearchReservedInstances = (output: any, context: __SerdeContext): O
 
 // de_OpenSearchReservedInstancesConfiguration omitted.
 
+/**
+ * deserializeAws_json1_0RdsDbInstance
+ */
+const de_RdsDbInstance = (output: any, context: __SerdeContext): RdsDbInstance => {
+  return take(output, {
+    configuration: _json,
+    costCalculation: (_: any) => de_ResourceCostCalculation(_, context),
+  }) as any;
+};
+
+// de_RdsDbInstanceConfiguration omitted.
+
+/**
+ * deserializeAws_json1_0RdsDbInstanceStorage
+ */
+const de_RdsDbInstanceStorage = (output: any, context: __SerdeContext): RdsDbInstanceStorage => {
+  return take(output, {
+    configuration: (_: any) => de_RdsDbInstanceStorageConfiguration(_, context),
+    costCalculation: (_: any) => de_ResourceCostCalculation(_, context),
+  }) as any;
+};
+
+/**
+ * deserializeAws_json1_0RdsDbInstanceStorageConfiguration
+ */
+const de_RdsDbInstanceStorageConfiguration = (
+  output: any,
+  context: __SerdeContext
+): RdsDbInstanceStorageConfiguration => {
+  return take(output, {
+    allocatedStorageInGb: __limitedParseDouble,
+    iops: __limitedParseDouble,
+    storageThroughput: __limitedParseDouble,
+    storageType: __expectString,
+  }) as any;
+};
+
 /**
  * deserializeAws_json1_0RdsReservedInstances
  */
@@ -936,6 +978,16 @@ const de_ResourceDetails = (output: any, context: __SerdeContext): ResourceDetai
       openSearchReservedInstances: de_OpenSearchReservedInstances(output.openSearchReservedInstances, context),
     };
   }
+  if (output.rdsDbInstance != null) {
+    return {
+      rdsDbInstance: de_RdsDbInstance(output.rdsDbInstance, context),
+    };
+  }
+  if (output.rdsDbInstanceStorage != null) {
+    return {
+      rdsDbInstanceStorage: de_RdsDbInstanceStorage(output.rdsDbInstanceStorage, context),
+    };
+  }
   if (output.rdsReservedInstances != null) {
     return {
       rdsReservedInstances: de_RdsReservedInstances(output.rdsReservedInstances, context),
diff --git a/codegen/sdk-codegen/aws-models/cost-optimization-hub.json b/codegen/sdk-codegen/aws-models/cost-optimization-hub.json
index 851f1ca0ab50..53d322bf1609 100644
--- a/codegen/sdk-codegen/aws-models/cost-optimization-hub.json
+++ b/codegen/sdk-codegen/aws-models/cost-optimization-hub.json
@@ -936,6 +936,20 @@
     "com.amazonaws.costoptimizationhub#Datetime": {
       "type": "timestamp"
     },
+    "com.amazonaws.costoptimizationhub#DbInstanceConfiguration": {
+      "type": "structure",
+      "members": {
+        "dbInstanceClass": {
+          "target": "smithy.api#String",
+          "traits": {
+            "smithy.api#documentation": "<p>The DB instance class of the DB instance.</p>"
+          }
+        }
+      },
+      "traits": {
+        "smithy.api#documentation": "<p>The DB instance configuration used for recommendations.</p>"
+      }
+    },
     "com.amazonaws.costoptimizationhub#EbsVolume": {
       "type": "structure",
       "members": {
@@ -1690,7 +1704,7 @@
         "estimatedMonthlyCost": {
           "target": "smithy.api#Double",
           "traits": {
-            "smithy.api#documentation": "<p>The estimated monthly cost of the recommendation.</p>"
+            "smithy.api#documentation": "<p>The estimated monthly cost of the current resource. For Reserved Instances and Savings Plans, it refers to the cost for eligible usage.</p>"
           }
         },
         "implementationEffort": {
@@ -2307,6 +2321,88 @@
         "smithy.api#documentation": "<p>Defines how rows will be sorted in the response.</p>"
       }
     },
+    "com.amazonaws.costoptimizationhub#RdsDbInstance": {
+      "type": "structure",
+      "members": {
+        "configuration": {
+          "target": "com.amazonaws.costoptimizationhub#RdsDbInstanceConfiguration",
+          "traits": {
+            "smithy.api#documentation": "<p>The Amazon RDS DB instance configuration used for recommendations.</p>"
+          }
+        },
+        "costCalculation": {
+          "target": "com.amazonaws.costoptimizationhub#ResourceCostCalculation"
+        }
+      },
+      "traits": {
+        "smithy.api#documentation": "<p>Contains the details of an Amazon RDS DB instance.</p>",
+        "smithy.api#tags": ["rds"]
+      }
+    },
+    "com.amazonaws.costoptimizationhub#RdsDbInstanceConfiguration": {
+      "type": "structure",
+      "members": {
+        "instance": {
+          "target": "com.amazonaws.costoptimizationhub#DbInstanceConfiguration",
+          "traits": {
+            "smithy.api#documentation": "<p>Details about the instance configuration.</p>"
+          }
+        }
+      },
+      "traits": {
+        "smithy.api#documentation": "<p>The Amazon RDS DB instance configuration used for recommendations.</p>"
+      }
+    },
+    "com.amazonaws.costoptimizationhub#RdsDbInstanceStorage": {
+      "type": "structure",
+      "members": {
+        "configuration": {
+          "target": "com.amazonaws.costoptimizationhub#RdsDbInstanceStorageConfiguration",
+          "traits": {
+            "smithy.api#documentation": "<p>The Amazon RDS DB instance storage configuration used for recommendations.</p>"
+          }
+        },
+        "costCalculation": {
+          "target": "com.amazonaws.costoptimizationhub#ResourceCostCalculation"
+        }
+      },
+      "traits": {
+        "smithy.api#documentation": "<p>Contains the details of an Amazon RDS DB instance storage.</p>",
+        "smithy.api#tags": ["rds"]
+      }
+    },
+    "com.amazonaws.costoptimizationhub#RdsDbInstanceStorageConfiguration": {
+      "type": "structure",
+      "members": {
+        "storageType": {
+          "target": "smithy.api#String",
+          "traits": {
+            "smithy.api#documentation": "<p>The storage type to associate with the DB instance.</p>"
+          }
+        },
+        "allocatedStorageInGb": {
+          "target": "smithy.api#Double",
+          "traits": {
+            "smithy.api#documentation": "<p>The new amount of storage in GB to allocate for the DB instance.</p>"
+          }
+        },
+        "iops": {
+          "target": "smithy.api#Double",
+          "traits": {
+            "smithy.api#documentation": "<p>The amount of Provisioned IOPS (input/output operations per second) to be initially\n      allocated for the DB instance.</p>"
+          }
+        },
+        "storageThroughput": {
+          "target": "smithy.api#Double",
+          "traits": {
+            "smithy.api#documentation": "<p>The storage throughput for the DB instance.</p>"
+          }
+        }
+      },
+      "traits": {
+        "smithy.api#documentation": "<p>The Amazon RDS DB instance storage configuration used for recommendations.</p>"
+      }
+    },
     "com.amazonaws.costoptimizationhub#RdsReservedInstances": {
       "type": "structure",
       "members": {
@@ -2497,7 +2593,7 @@
         "estimatedMonthlyCost": {
           "target": "smithy.api#Double",
           "traits": {
-            "smithy.api#documentation": "<p>The estimated monthly cost for the recommendation.</p>"
+            "smithy.api#documentation": "<p>The estimated monthly cost of the current resource. For Reserved Instances and Savings Plans, it refers to the cost for eligible usage.</p>"
           }
         },
         "currencyCode": {
@@ -2897,6 +2993,20 @@
           "traits": {
             "smithy.api#documentation": "<p>The SageMaker Savings Plans recommendation details.</p>"
           }
+        },
+        "rdsDbInstance": {
+          "target": "com.amazonaws.costoptimizationhub#RdsDbInstance",
+          "traits": {
+            "smithy.api#documentation": "<p>The DB instance recommendation details.</p>",
+            "smithy.api#tags": ["rds"]
+          }
+        },
+        "rdsDbInstanceStorage": {
+          "target": "com.amazonaws.costoptimizationhub#RdsDbInstanceStorage",
+          "traits": {
+            "smithy.api#documentation": "<p>The DB instance storage recommendation details.</p>",
+            "smithy.api#tags": ["rds"]
+          }
         }
       },
       "traits": {
@@ -3050,6 +3160,20 @@
           "traits": {
             "smithy.api#enumValue": "ElastiCacheReservedInstances"
           }
+        },
+        "RDS_DB_INSTANCE_STORAGE": {
+          "target": "smithy.api#Unit",
+          "traits": {
+            "smithy.api#enumValue": "RdsDbInstanceStorage",
+            "smithy.api#tags": ["rds"]
+          }
+        },
+        "RDS_DB_INSTANCE": {
+          "target": "smithy.api#Unit",
+          "traits": {
+            "smithy.api#enumValue": "RdsDbInstance",
+            "smithy.api#tags": ["rds"]
+          }
         }
       }
     },