# Auto scaling group

Auto-scaling is useful to easily scale the number of EC2 instances up or down at need.

After deploying the WEKA cluster via CloudFormation, it is possible to create an auto-scaling group to ease the WEKA cluster size management.

You can create an auto-scaling group for your cluster by running the [wekactl utility](https://github.com/weka/wekactl).

You can control the number of instances by either changing the desired capacity of instances from the AWS auto-scaling group console or defining your custom metrics and scaling policy in AWS. Once the desired capacity has changed, WEKA takes care of safely scaling the instances.

{% hint style="info" %}
When scaling the number of instances increase/decrease and, along with that, the cluster resources, to automatically take advantage of the extra SSD capacity, it is possible to use [thin-provisioned](https://docs.weka.io/4.2/overview/filesystems#thin-provisioning) filesystems.

When downscaling, ensure the minimum SSD capacity of the filesystems can fit into the lower capacity cluster or tiered to S3. 
{% endhint %}

For more information and documentation on the utility, refer to the [wekactl GitHub repository](https://github.com/weka/wekactl).