# Online vertical scaling by modifying node type
By using online vertical scaling with MemoryDB, you can scale your cluster dynamically with minimal downtime. This allows your cluster to serve requests even while scaling.
**Note**
Scaling is not supported between a data tiering cluster (for example, a cluster using an r6gd node type) and a cluster that does not use data tiering (for example, a cluster using an r6g node type). For more information, see [Data tiering](data-tiering.md).
You can do the following:
+ **Scale up** – Increase read and write capacity by adjusting the node type of your MemoryDB cluster to use a larger node type.
MemoryDB dynamically resizes your cluster while remaining online and serving requests.
+ **Scale down** – Reduce read and write capacity by adjusting the node type down to use a smaller node. Again, MemoryDB dynamically resizes your cluster while remaining online and serving requests. In this case, you reduce costs by downsizing the node.
**Note**
The scale up and scale down processes rely on creating clusters with newly selected node types and synchronizing the new nodes with the previous ones. To ensure a smooth scale up/down flow, do the following:
While the vertical scaling process is designed to remain fully online, it does rely on synchronizing data between the old node and the new node. We recommend that you initiate scale up/down during hours when you expect data traffic to be at its minimum.
Test your application behavior during scaling in a staging environment, if possible.
# Online scaling up
**Topics**
+ [Scaling up MemoryDB clusters (Console)](#cluster-vertical-scaling-console)
+ [Scaling up MemoryDB clusters (AWS CLI)](#scaling.scaleUp.cli)
+ [Scaling up MemoryDB clusters (MemoryDB API)](#verticalscaling.scaleup.api)
## Scaling up MemoryDB clusters (Console)
The following procedure describes how to scale up a MemoryDB cluster using the AWS Management Console. During this process, your MemoryDB cluster will continue to serve requests with minimal downtime.
**To scale up a cluster (console)**
1. Sign in to the AWS Management Console and open the MemoryDB console at [https://console.aws.amazon.com/memorydb/](https://console.aws.amazon.com/memorydb/).
1. From the list of clusters, choose the cluster.
1. Choose **Actions** and then choose **Modify**.
1. In the **Modify Cluster** dialog:
1. Choose the node type you want to scale to from the **Node type** list. To scale up, select a node type larger than your existing node.
1. Choose **Save changes**.
The cluster's status changes to *modifying*. When the status changes to *available*, the modification is complete and you can begin using the new cluster.
## Scaling up MemoryDB clusters (AWS CLI)
The following procedure describes how to scale up a MemoryDB cluster using the AWS CLI. During this process, your MemoryDB cluster will continue to serve requests with minimal downtime.
**To scale up a MemoryDB cluster (AWS CLI)**
1. Determine the node types you can scale up to by running the AWS CLI `list-allowed-node-type-updates` command with the following parameter.
For Linux, macOS, or Unix:
```
aws memorydb list-allowed-node-type-updates \
--cluster-name my-cluster-name
```
For Windows:
```
aws memorydb list-allowed-node-type-updates ^
--cluster-name my-cluster-name
```
Output from the above command looks something like this (JSON format).
```
{
"ScaleUpNodeTypes": [
"db.r6g.2xlarge",
"db.r6g.large"
],
"ScaleDownNodeTypes": [
"db.r6g.large"
],
}
```
For more information, see [list-allowed-node-type-updates](https://docs.aws.amazon.com/cli/latest/reference/memorydb/list-allowed-node-type-updates.html) in the *AWS CLI Reference*.
1. Modify your cluster to scale up to the new, larger node type, using the AWS CLI `update-cluster` command and the following parameters.
+ `--cluster-name` – The name of the cluster you are scaling up to.
+ `--node-type` – The new node type you want to scale the cluster. This value must be one of the node types returned by the `list-allowed-node-type-updates` command in step 1.
For Linux, macOS, or Unix:
```
aws memorydb update-cluster \
--cluster-name my-cluster \
--node-type db.r6g.2xlarge
```
For Windows:
```
aws memorydb update-cluster ^
--cluster-name my-cluster ^
--node-type db.r6g.2xlarge ^
```
For more information, see [update-cluster](https://docs.aws.amazon.com/cli/latest/reference/memorydb/update-cluster.html).
## Scaling up MemoryDB clusters (MemoryDB API)
The following process scales your cluster from its current node type to a new, larger node type using the MemoryDB API. During this process, MemoryDB updates the DNS entries so they point to the new nodes. You can scale auto-failover enabled clusters while the cluster continues to stay online and serve incoming requests.
The amount of time it takes to scale up to a larger node type varies, depending upon your node type and the amount of data in your current cluster.
**To scale up a MemoryDB cluster (MemoryDB API)**
1. Determine which node types you can scale up to using the MemoryDB API `ListAllowedNodeTypeUpdates` action with the following parameter.
+ `ClusterName` – the name of the cluster. Use this parameter to describe a specific cluster rather than all clusters.
```
https://memory-db.us-east-1.amazonaws.com/
?Action=ListAllowedNodeTypeUpdates
&ClusterName=MyCluster
&Version=2021-01-01
&SignatureVersion=4
&SignatureMethod=HmacSHA256
&Timestamp=20210802T192317Z
&X-Amz-Credential=
```
For more information, see [ListAllowedNodeTypeUpdates](https://docs.aws.amazon.com/memorydb/latest/APIReference/API_ListAllowedNodeTypeUpdates.html) in the *MemoryDB API Reference*.
1. Scale your current cluster up to the new node type using the `UpdateCluster` MemoryDB API action and with the following parameters.
+ `ClusterName` – the name of the cluster.
+ `NodeType` – the new, larger node type of the clusters in this cluster. This value must be one of the instance types returned by the `ListAllowedNodeTypeUpdates` action in step 1.
```
https://memory-db.us-east-1.amazonaws.com/
?Action=UpdateCluster
&NodeType=db.r6g.2xlarge
&ClusterName=myCluster
&SignatureVersion=4
&SignatureMethod=HmacSHA256
&Timestamp=20210801T220302Z
&Version=2021-01-01
&X-Amz-Algorithm=Amazon4-HMAC-SHA256
&X-Amz-Date=20210801T220302Z
&X-Amz-SignedHeaders=Host
&X-Amz-Expires=20210801T220302Z
&X-Amz-Credential=
&X-Amz-Signature=
```
For more information, see [UpdateCluster](https://docs.aws.amazon.com/memorydb/latest/APIReference/API_UpdateCluster.html).
# Online scaling down
**Topics**
+ [Scaling down MemoryDB clusters (Console)](#cluster-vertical-scaling-down-console)
+ [Scaling down MemoryDB clusters (AWS CLI)](#scaling.scaledown.cli)
+ [Scaling down MemoryDB clusters (MemoryDB API)](#scaling.vertical.scaledown.api)
## Scaling down MemoryDB clusters (Console)
The following procedure describes how to scale down a MemoryDB cluster using the AWS Management Console. During this process, your MemoryDB cluster will continue to serve requests with minimal downtime.
**To scale down a MemoryDB cluster (console)**
1. Sign in to the AWS Management Console and open the MemoryDB console at [https://console.aws.amazon.com/memorydb/](https://console.aws.amazon.com/memorydb/).
1. From the list of clusters, choose your preferred cluster.
1. Choose **Actions** and then choose **Modify**.
1. In the **Modify Cluster** dialog:
1. Choose the node type you want to scale to from the **Node type** list. To scale down, select a node type smaller than your existing node. Note that not all node types are available to scale down to.
1. Choose **Save changes**.
The cluster's status changes to *modifying*. When the status changes to *available*, the modification is complete and you can begin using the new cluster.
## Scaling down MemoryDB clusters (AWS CLI)
The following procedure describes how to scale down a MemoryDB cluster using the AWS CLI. During this process, your MemoryDB cluster will continue to serve requests with minimal downtime.
**To scale down a MemoryDB cluster (AWS CLI)**
1. Determine the node types you can scale down to by running the AWS CLI `list-allowed-node-type-updates` command with the following parameter.
For Linux, macOS, or Unix:
```
aws memorydb list-allowed-node-type-updates \
--cluster-name my-cluster-name
```
For Windows:
```
aws memorydb list-allowed-node-type-updates ^
--cluster-name my-cluster-name
```
Output from the above command looks something like this (JSON format).
```
{
"ScaleUpNodeTypes": [
"db.r6g.2xlarge",
"db.r6g.large"
],
"ScaleDownNodeTypes": [
"db.r6g.large"
],
}
```
For more information, see [list-allowed-node-type-updates](https://docs.aws.amazon.com/cli/latest/reference/memorydb/list-allowed-node-type-updates.html).
1. Modify your cluster to scale down to the new, smaller node type, using the `update-cluster` command and the following parameters.
+ `--cluster-name` – The name of the cluster you are scaling down to.
+ `--node-type` – The new node type you want to scale the cluster. This value must be one of the node types returned by the `list-allowed-node-type-updates` command in step 1.
For Linux, macOS, or Unix:
```
aws memorydb update-cluster \
--cluster-name my-cluster \
--node-type db.r6g.large
```
For Windows:
```
aws memorydb update-cluster ^
--cluster-name my-cluster ^
--node-type db.r6g.large
```
For more information, see [update-cluster](https://docs.aws.amazon.com/cli/latest/reference/memorydb/update-cluster.html).
## Scaling down MemoryDB clusters (MemoryDB API)
The following process scales your cluster from its current node type to a new, smaller node type using the MemoryDB API. During this process, your MemoryDB cluster will continue to serve requests with minimal downtime.
The amount of time it takes to scale down to a smaller node type varies, depending upon your node type and the amount of data in your current cluster.
**Scaling down (MemoryDB API)**
1. Determine which node types you can scale down to using the [ListAllowedNodeTypeUpdates](https://docs.aws.amazon.com/memorydb/latest/APIReference/API_ListAllowedNodeTypeUpdates.html) API with the following parameter:
+ `ClusterName` – the name of the cluster. Use this parameter to describe a specific cluster rather than all clusters.
```
https://memory-db.us-east-1.amazonaws.com/
?Action=ListAllowedNodeTypeUpdates
&ClusterName=MyCluster
&Version=2021-01-01
&SignatureVersion=4
&SignatureMethod=HmacSHA256
&Timestamp=20210802T192317Z
&X-Amz-Credential=
```
1. Scale your current cluster down to the new node type using the [UpdateCluster](https://docs.aws.amazon.com/memorydb/latest/APIReference/API_UpdateCluster.html) API with the following parameters.
+ `ClusterName` – the name of the cluster.
+ `NodeType` – the new, smaller node type of the clusters in this cluster. This value must be one of the instance types returned by the `ListAllowedNodeTypeUpdates` action in step 1.
```
https://memory-db.us-east-1.amazonaws.com/
?Action=UpdateCluster
&NodeType=db.r6g.2xlarge
&ClusterName=myReplGroup
&SignatureVersion=4
&SignatureMethod=HmacSHA256
&Timestamp=20210801T220302Z
&Version=2021-01-01
&X-Amz-Algorithm=Amazon4-HMAC-SHA256
&X-Amz-Date=20210801T220302Z
&X-Amz-SignedHeaders=Host
&X-Amz-Expires=20210801T220302Z
&X-Amz-Credential=
&X-Amz-Signature=
```