# Monitoring the upload buffer
<a name="PerfUploadBuffer-common"></a>

You can find information following about how to monitor a gateway's upload buffer and how to create an alarm so that you get a notification when the buffer exceeds a specified threshold. By using this approach, you can add buffer storage to a gateway before it fills completely and your storage application stops backing up to AWS.

You monitor the upload buffer in the same way in both the cached-volume and Tape Gateway architectures. For more information, see [How Volume Gateway works](StorageGatewayConcepts.md).

**Note**  
The `WorkingStoragePercentUsed`, `WorkingStorageUsed`, and `WorkingStorageFree` metrics represent the upload buffer for stored volumes only before the release of the cached-volume feature in Storage Gateway. Now, use the equivalent upload buffer metrics `UploadBufferPercentUsed`, `UploadBufferUsed`, and `UploadBufferFree`. These metrics apply to both gateway architectures.


| Item of Interest | How to Measure | 
| --- | --- | 
| Upload buffer usage |  Use the `UploadBufferPercentUsed`, `UploadBufferUsed`, and `UploadBufferFree` metrics with the `Average` statistic. For example, use the `UploadBufferUsed` with the `Average` statistic to analyze the storage usage over a time period.  | <a name="PerfUploadBufferMeasuring-common"></a>

**To measure the percent of the upload buffer that is used**

1. Open the CloudWatch console at [https://console.aws.amazon.com/cloudwatch/](https://console.aws.amazon.com/cloudwatch/).

1. Choose the **StorageGateway: Gateway Metrics** dimension, and find the gateway that you want to work with.

1. Choose the `UploadBufferPercentUsed` metric.

1. For **Time Range**, choose a value.

1. Choose the `Average` statistic.

1. For **Period**, choose a value of 5 minutes to match the default reporting time.

The resulting time-ordered set of data points contains the percent used of the upload buffer.

Using the following procedure, you can create an alarm using the CloudWatch console. To learn more about alarms and thresholds, see [Creating CloudWatch Alarms](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/AlarmThatSendsEmail.html) in the *Amazon CloudWatch User Guide*.<a name="GatewayAlarm1-common"></a>

**To set an upper threshold alarm for a gateway's upload buffer**

1. Open the CloudWatch console at [https://console.aws.amazon.com/cloudwatch/](https://console.aws.amazon.com/cloudwatch/).

1. Choose **Create Alarm** to start the Create Alarm wizard.

1. Specify a metric for your alarm:

   1. On the **Select Metric** page of the Create Alarm wizard, choose the **AWS/StorageGateway:GatewayId,GatewayName** dimension, and then find the gateway that you want to work with.

   1. Choose the `UploadBufferPercentUsed` metric. Use the `Average` statistic and a period of 5 minutes.

   1. Choose **Continue**.

1. Define the alarm name, description, and threshold:

   1. On the **Define Alarm** page of the Create Alarm wizard, identify your alarm by giving it a name and description in the **Name** and **Description** boxes.

   1. Define the alarm threshold.

   1. Choose **Continue**.

1. Configure an email action for the alarm:

   1. On the **Configure Actions** page of the Create Alarm wizard, choose **Alarm** for **Alarm State**.

   1. Choose **Choose or create email topic** for **Topic**.

      To create an email topic means that you set up an Amazon SNS topic. For more information about Amazon SNS, see [Set Up Amazon SNS](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/US_SetupSNS.html) in the *Amazon CloudWatch User Guide.*

   1. For **Topic**, enter a descriptive name for the topic.

   1. Choose **Add Action**.

      

   1. Choose **Continue**.

1. Review the alarm settings, and then create the alarm:

   1. On the **Review** page of the Create Alarm wizard, review the alarm definition, metric, and associated actions to take (for example, sending an email notification).

   1. After reviewing the alarm summary, choose **Save Alarm**.

1. Confirm your subscription to the alarm topic:

   1. Open the Amazon SNS email that was sent to the email address that you specified when creating the topic.

   1. Confirm your subscription by clicking the link in the email.

      A subscription confirmation appears.