# Managing throughput capacity
You can increase and decrease your file system's throughput capacity to help manage its performance at any time. Throughput capacity is one of the dimensions that determines the speed at which the file server hosting your FSx for Windows File Server file system can serve data. Higher levels of throughput capacity also come with higher levels of I/O operations per second (IOPS) and a larger amount of cache memory on the file server. For more information, see [FSx for Windows File Server performancePerformance](performance.md).
**Topics**
+ [How throughput scaling works](#how-throughput-scaling-works)
+ [Knowing when to modify throughput capacity](#when-to-modify-throughput-capacity)
+ [Modifying throughput capacity](increase-throughput-capacity.md)
+ [Monitoring throughput capacity updates](monitoring-throughput-capacity-changes.md)
## How throughput scaling works
When you modify your file system's throughput capacity, Amazon FSx switches out the file system's file server to one with more or less throughput behind the scenes. For Multi-AZ file systems, switching to a new file server triggers an automatic failover and failback while Amazon FSx switches out the preferred and secondary file servers. Single-AZ file systems will be unavailable for a few minutes while the file server is switched during throughput capacity scaling. You are billed for the new amount of throughput capacity once it becomes available to your file system.
**Note**
During a maintenance operation on the back end, system modifications (including throughput capacity modifications) may be delayed. Maintenance operations can cause system modifications to queue up to be processed.
For Multi-AZ file systems, throughput capacity scaling results in an automatic failover and failback while Amazon FSx switches out the preferred and secondary file servers. During file server replacements, which happen during throughput capacity scaling as well as file system maintenance and an unplanned service disruption, any ongoing traffic to the file system will be served by the remaining file server. When the replaced file server is back online, FSx for Windows will run a resynchronization job to ensure that data is synced back to the newly replaced file server.
FSx for Windows is designed to minimize the impact of this resynchronization activity on application and users. However, the resynchronization process involves synchronizing data in large blocks. This means that a large block of data can require synchronization even if only a small portion is updated. Consequently, the amount of resynchronization depends not only on the amount of data churn, but also the nature of the data churn on the file system. If your workload is write-heavy and IOPS-heavy, the data synchronization process may take longer and require additional performance resources.
Your file system will continue to be available during this time, but in order to reduce the duration of data synchronization, we recommend modifying throughput capacity during idle periods when there is minimal load on your file system. We also recommend ensuring that your file system has sufficient throughput capacity to run the synchronization job in addition to your workload, in order to reduce the duration of data synchronization. Lastly, we recommend testing the impact of failovers while your file system has a lighter load.
## Knowing when to modify throughput capacity
Amazon FSx integrates with Amazon CloudWatch, enabling you to monitor your file system's ongoing throughput usage levels. The performance (throughput and IOPS) that you can drive through your file system depends on your specific workload’s characteristics, along with your file system’s throughput capacity, storage capacity, and storage type. You can use CloudWatch metrics to determine which of these dimensions to change to improve performance. For more information, see [Monitoring with Amazon CloudWatch](monitoring-cloudwatch.md).
FSx for Windows File Server provides performance alerts based on values of CloudWatch metrics for your file system in the Monitoring & performance dashboard in the File system details page on the Amazon FSx console. This includes throughput capacity, and other file system metrics that can benefit from throughput capacity increases. For more information, see [Performance warnings and recommendations](monitoring-cloudwatch.md#performance-insights-FSxW).
Configure your file system with sufficient throughput capacity to meet not only the expected traffic of your workload, but also additional performance resources that are needed to support the features you enable on your file system. For example, if you’re running data deduplication, the throughput capacity that you select must provide enough memory to run deduplication based on the storage that you have. If you’re using shadow copies, increase throughput capacity to a value that's at least three times the value that's expected to be driven by your workload to avoid Windows Server deleting your shadow copies. For more information, see [Impact of throughput capacity on performance](performance.md#impact-throughput-cap-performance).
# Modifying throughput capacity
You can increase or decrease your file system's throughput capacity using the Amazon FSx console, the AWS Command Line Interface (AWS CLI), or the Amazon FSx API, as described in the following procedures.
## To modify a file system's throughput capacity (console)
1. Open the Amazon FSx console at [https://console.aws.amazon.com/fsx/](https://console.aws.amazon.com/fsx/).
1. Navigate to **File systems**, and choose the Windows file system that you want to increase the throughput capacity for.
1. For **Actions**, choose **Update throughput**.
Or, in the **Summary** panel, choose **Update** next to the file system's **Throughput capacity**.
The **Update throughput capacity** window appears.
1. Choose the new value for **Throughput capacity** from the list.
1. Choose **Update** to initiate the throughput capacity update.
**Note**
Multi-AZ file systems fail over and fail back when updating throughput scaling, and are fully available. Single-AZ file systems experience a very brief period of unavailability during the update.
1. You can monitor the update progress on the **File systems** detail page, in the **Updates** tab.
You can monitor the progress of the update by using the Amazon FSx console, the AWS CLI, and the API. For more information, see [Monitoring throughput capacity updates](monitoring-throughput-capacity-changes.md).
## To modify a file system's throughput capacity (CLI)
To increase or decrease a file system's throughput capacity, use the AWS CLI command [update-file-system](https://docs.aws.amazon.com/cli/latest/reference/fsx/update-file-system.html). Set the following parameters:
+ `--file-system-id` to the ID of the file system that you are updating.
+ `ThroughputCapacity` to the desired value; valid values are 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4608, 6144, 9216, 12288 MBps.
You can monitor the progress of the update by using the Amazon FSx console, the AWS CLI, and the API. For more information, see [Monitoring throughput capacity updates](monitoring-throughput-capacity-changes.md).
# Monitoring throughput capacity updates
You can monitor the progress of a throughput capacity modification using the Amazon FSx console, the API, and the AWS CLI.
## Monitoring throughput capacity changes in the console
In the **Updates** tab in the **File system details** window, you can view the 10 most recent update actions for each update action type.
![\[Console screen shot showing the file system updates window.\]](http://docs.aws.amazon.com/fsx/latest/WindowsGuide/images/fs-updates-panel.png)
For throughput capacity update actions, you can view the following information.
****Update type****
Possible value is **Throughput capacity**.
****Target value****
The desired value to change the file system's throughput capacity to.
****Status****
The current status of the update. For throughput capacity updates, the possible values are as follows:
+ **Pending** – Amazon FSx has received the update request, but has not started processing it.
+ **In progress** – Amazon FSx is processing the update request.
+ **Updated optimizing** – Amazon FSx has updated the file system's network I/O, CPU, and memory resources. The new disk I/O performance level is available for write operations. Your read operations will see disk I/O performance between the previous level and the new level until your file system is no longer in the this state.
+ **Completed** – The throughput capacity update completed successfully.
+ **Failed** – The throughput capacity update failed. Choose the question mark (**?**) to see details on why the throughput update failed.
****Request time****
The time that Amazon FSx received the update request.
## Monitoring changes with the AWS CLI and API
You can view and monitor file system throughput capacity modification requests using the [describe-file-systems](https://docs.aws.amazon.com/cli/latest/reference/fsx/describe-file-systems.html) CLI command and the [DescribeFileSystems](https://docs.aws.amazon.com/fsx/latest/APIReference/API_DescribeFileSystems.html) API action. The `AdministrativeActions` array lists the 10 most recent update actions for each administrative action type. When you modify a file system's throughput capacity, a `FILE_SYSTEM_UPDATE` administrative action is generated.
The following example shows the response excerpt of a `describe-file-systems` CLI command. The file system has a throughput capacity of 8 MBps, and the target throughput capacity of 256 MBps.
```
.
.
.
"ThroughputCapacity": 8,
"AdministrativeActions": [
{
"AdministrativeActionType": "FILE_SYSTEM_UPDATE",
"RequestTime": 1581694764.757,
"Status": "PENDING",
"TargetFileSystemValues": {
"WindowsConfiguration": {
"ThroughputCapacity": 256
}
}
}
]
```
When Amazon FSx completes processing the action successfully, the status changes to `COMPLETED`. The new throughput capacity is then available to the file system, and shows in the `ThroughputCapacity` property. This is shown in the following response excerpt of a **describe-file-systems** CLI command.
```
.
.
.
"ThroughputCapacity": 256,
"AdministrativeActions": [
{
"AdministrativeActionType": "FILE_SYSTEM_UPDATE",
"RequestTime": 1581694764.757,
"Status": "COMPLETED",
"TargetFileSystemValues": {
"WindowsConfiguration": {
"ThroughputCapacity": 256
}
}
}
]
```
If the throughput capacity modification fails, the status changes to `FAILED`, and the `FailureDetails` property provides information about the failure. For information about troubleshooting failed actions, see [Storage or throughput capacity updates fail](admin-actions-ts.md).