NEW - You can now accelerate your migration and modernization with AWS Transform. Read [Getting Started](https://docs.aws.amazon.com/transform/latest/userguide/getting-started.html) in the *AWS Transform User Guide*.

# Instance type right-sizing


AWS Application Migration Service launches a new instance type after every change of configuration on the source server, for example, added/removed disks, and added/removed RAM. When you use the instance type right-sizing feature Application Migration Service launches a test or cutover instance type that best matches the OS, CPU, and RAM of your source server. Set this feature to **On** to enable or to **None** to disable, in which case Application Migration Service launches the instance type as configured in your Amazon EC2 launch template. 

Enable instance type right-sizing if you want to determine the instance type that is launched in AWS for all your test or cutover servers.

**Important considerations:**
+ The AWS instance type selected by AWS Application Migration Service when this feature is activated overwrites the instance type defined in your EC2 launch template.
+ Hardware changes and the resulting AWS instance type change may take up to 90 minutes to be processed by AWS Application Migration Service. 
+ The T family instance type is not supported for right-sizing. If you want to use the T family, avoid using right-sizing.
+ The available capacity for each Amazon EC2 instance type varies by Availability Zone and Region, and may be subject to your specific AWS account limits. For mission-critical workloads consider using [Reserved Instances](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-reserved-instances.html) to guarantee capacity for specific instance types. Note that additional costs apply when reserving capacity.
+ The right-sizing instance type selected by AWS Application Migration Service appears on the **Server details** tab. 

**Supported instance families:**  
The service provides recommendations from these instance families, which are available in most target Regions:
+ c5
+ m5
+ c4
+ m4
+ r5
+ r4
+ i3
+ d2

  

**Supported instance families for the Thailand and Malaysia Regions:**  
The *Asia Pacific (Thailand) *, and *Asia Pacific (Malaysia) * Regions support only these instance families:
+ C6i
+ m6i
+ r6i