# Monitoring Your Tape Gateway
This topics in this section describe procedures and conceptual information about how to monitor your Tape Gateway. You can monitor the virtual tapes, cache storage, and the upload buffer that are associated with your Tape Gateway. You use the AWS Management Console to view metrics for your Tape Gateway. With metrics, you can track the health of your Tape Gateway and set up alarms to notify you when one or more metrics are outside a defined threshold.
You can use Amazon CloudWatch Logs to get information about the health of your Tape Gateway and related resources. You can use the logs to monitor your gateway for errors that it encounters. In addition, you can use Amazon CloudWatch subscription filters to automate processing of the log information in real time.
Storage Gateway provides CloudWatch metrics at no additional charge. Storage Gateway metrics are recorded for a period of two weeks. By using these metrics, you can access historical information and get a better perspective of how your Tape Gateway and virtual tapes are performing. For detailed information about CloudWatch, see the [https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/WhatIsCloudWatch.html](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/WhatIsCloudWatch.html).
Data throughput, data latency, and operations per second are measures that you can use to understand how your storage applications are performing with Tape Gateway. When you use the correct aggregation statistic, these values can be measured by using the Storage Gateway metrics that are provided for you.
**Topics**
+ [Getting Tape Gateway health logs with CloudWatch log groups](cw-log-groups-tape.md)
+ [Using Amazon CloudWatch Metrics](UsingCloudWatchConsole-vtl-common.md)
+ [Understanding virtual tape metrics](monitoring-tape.md)
+ [Measuring Performance Between Your Tape Gateway and AWS](PerfGatewayAWS-vtl-common.md)
# Getting Tape Gateway health logs with CloudWatch log groups
You can use Amazon CloudWatch Logs to get information about the health of your Tape Gateway and related resources. You can use the logs to monitor your gateway for errors that it encounters. In addition, you can use Amazon CloudWatch subscription filters to automate processing of the log information in real time. For more information, see [Real-time Processing of Log Data with Subscriptions](https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/Subscriptions.html) in the *Amazon CloudWatch User Guide.*
For example, suppose that your gateway is deployed in a cluster activated with VMware HA and you need to know about any errors. You can configure a CloudWatch log group to monitor your gateway and get notified when your gateway encounters an error. You can either configure the group when you are activating the gateway or after your gateway is activated and up and running. For information about how to configure a CloudWatch log group when activating a gateway, see [Configure your Tape Gateway](https://docs.aws.amazon.com/storagegateway/latest/tgw/create-gateway-vtl.html#configure-gateway-tape). For general information about CloudWatch log groups, see [Working with Log Groups and Log Streams](https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/Working-with-log-groups-and-streams.html) in the *Amazon CloudWatch User Guide.*
For information about how to troubleshoot and fix these types of errors, see [Troubleshooting virtual tape issues](Main_TapesIssues-vtl.md).
The following procedure shows you how to configure a CloudWatch log group after your gateway is activated.
**To configure a CloudWatch Log Group to work with your File Gateway**
1. Sign in to the AWS Management Console and open the Storage Gateway console at [https://console.aws.amazon.com/storagegateway/home](https://console.aws.amazon.com/storagegateway/).
1. In the navigation pane, choose **Gateways**, and then choose the gateway that you want to configure the CloudWatch Log Group for.
1. For **Actions**, choose **Edit gateway information** or on the **Details** tab, under **Health logs** and **Not Enabled**, choose **Configure log group** to open the **Edit *CustomerGatewayName*** dialog box.
1. For **Gateway health log group**, choose one of the following:
+ **Disable logging** if you don't want to monitor your gateway using CloudWatch log groups.
+ **Create a new log group** to create a new CloudWatch log group.
+ **Use an existing log group** to use a CloudWatch log group that already exists.
Choose a log group from the **Existing log group list**.
1. Choose **Save changes**.
1. To see the health logs for your gateway, do the following:
1. In the navigation pane, choose **Gateways**, and then choose the gateway that you configured the CloudWatch Log Group for.
1. Choose the **Details** tab, and under **Health logs**, choose **CloudWatch Logs**. The **Log group details** page opens in the CloudWatch console.
Following is an example of a Tape Gateway event message that is sent to CloudWatch. This example shows a `TapeStatusTransition` message.
```
{
"severity": "INFO",
"source": "FZTT16FCF5",
"type": "TapeStatusTransition",
"gateway": "sgw-C51DFEAC",
"timestamp": "1581553463831",
"newStatus": "RETRIEVED"
}
```
# Using Amazon CloudWatch Metrics
You can get monitoring data for your Tape Gateway by using either the AWS Management Console or the CloudWatch API. The console displays a series of graphs based on the raw data from the CloudWatch API. The CloudWatch API can also be used through one of the [Amazon AWS Software Development Kits (SDKs)](https://aws.amazon.com/tools) or the [Amazon CloudWatch API](https://aws.amazon.com/cloudwatch) tools. Depending on your needs, you might prefer to use either the graphs displayed in the console or retrieved from the API.
Regardless of which method you choose to use to work with metrics, you must specify the following information:
+ The metric dimension to work with. A *dimension* is a name-value pair that helps you to uniquely identify a metric. The dimensions for Storage Gateway are `GatewayId` and `GatewayName`. In the CloudWatch console, you can use the `Gateway Metrics` view to easily select gateway-specific and tape-specific dimensions. For more information about dimensions, see [Dimensions](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_concepts.html#Dimension) in the *Amazon CloudWatch User Guide*.
+ The metric name, such as `ReadBytes`.
The following table summarizes the types of Storage Gateway metric data that are available to you.
| Amazon CloudWatch Namespace | Dimension | Description |
| --- | --- | --- |
| AWS/StorageGateway | GatewayId, GatewayName | These dimensions filter for metric data that describes aspects of the Tape Gateway. You can identify a Tape Gateway to work with by specifying both the `GatewayId` and the `GatewayName` dimensions. Throughput and latency data of a Tape Gateway is based on all the virtual tapes in the Tape Gateway. Data is available automatically in 5-minute periods at no charge. |
Working with gateway and tape metrics is similar to working with other service metrics. You can find a discussion of some of the most common metrics tasks in the CloudWatch documentation listed following:
+ [Viewing Available Metrics](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/viewing_metrics_with_cloudwatch.html)
+ [Getting Statistics for a Metric](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/US_GetStatistics.html)
+ [Creating CloudWatch Alarms](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/AlarmThatSendsEmail.html)
# Understanding virtual tape metrics
You can find information following about the Storage Gateway metrics that cover virtual tapes. Each tape has a set of metrics associated with it.
Some tape-specific metrics might have the same name as certain gateway-specific metrics. These metrics represent the same kinds of measurements but are scoped to a tape instead of a gateway. Before starting work, specify whether you want to work with a gateway metric or a tape metric. When working with tape metrics, specify the tape ID for the tape that you want to view metrics for. For more information, see [Using Amazon CloudWatch Metrics](UsingCloudWatchConsole-vtl-common.md).
**Note**
Some metrics return data points only when new data has been generated during the most recent monitoring period.
The following table describes the Storage Gateway metrics that you can use to get information about your tapes.
| Metric | Description |
| --- | --- |
| CachePercentDirty | The tape's contribution to the overall percentage of the gateway's cache that isn't persisted to AWS. The sample is taken at the end of the reporting period. Use the `CachePercentDirty` metric of the gateway to view the overall percentage of the gateway's cache that isn't persisted to AWS. For more information, see [Understanding gateway metrics](MonitoringGateways-common.md). Units: Percent |
| CloudTraffic | The amount of bytes uploaded and downloaded from the cloud to the tape. Units: bytes |
| IoWaitPercent | The percentage of allocated IoWait units that are currently used by the tape. Units: Percent |
| HealthNotification | The number of health notifications sent by the tape. Units: count |
| MemUsedBytes | The percentage of allocated memory that is currently used by the tape. Units: Bytes |
| MemTotalBytes | The percentage of total memory that is currently used by the tape. Units: Bytes |
| ReadBytes | The total number of bytes read from your on-premises applications in the reporting period for a file share. Use this metric with the `Sum` statistic to measure throughput and with the `Samples` statistic to measure IOPS. Units: Bytes |
| UserCpuPercent | The percentage of allocated CPU compute units for the user that are currently used by the tape. Units: Percent |
| WriteBytes | The total number of bytes written to your on-premises applications in the reporting period. Use this metric with the `Sum` statistic to measure throughput and with the `Samples` statistic to measure IOPS. Units: Bytes |
# Measuring Performance Between Your Tape Gateway and AWS
Data throughput, data latency, and operations per second are measures that you can use to understand how your application storage that is using your Tape Gateway is performing. When you use the correct aggregation statistic, these values can be measured by using the Storage Gateway metrics that are provided for you.
A *statistic* is an aggregation of a metric over a specified period of time. When you view the values of a metric in CloudWatch, use the `Average` statistic for data latency (milliseconds), and use the `Samples` statistic for input/output operations per second (IOPS). For more information, see [Statistics](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_concepts.html#Statistic) in the *Amazon CloudWatch User Guide*.
The following table summarizes the metrics and the corresponding statistic you can use to measure the throughput, latency, and IOPS between your Tape Gateway and AWS.
| Item of Interest | How to Measure |
| --- | --- |
| Latency | Use the ReadTime and WriteTime metrics with the Average CloudWatch statistic. For example, the Average value of the ReadTime metric gives you the latency per operation over the sample period of time. |
| Throughput to AWS | Use the CloudBytesDownloaded and CloudBytesUploaded metrics with the Sum CloudWatch statistic. For example, the Sum value of the CloudBytesDownloaded metric over a sample period of 5 minutes divided by 300 seconds gives you the throughput from AWS to the Tape Gateway as a rate in bytes per second. |
| Latency of data to AWS | Use the CloudDownloadLatency metric with the Average statistic. For example, the Average statistic of the CloudDownloadLatency metric gives you the latency per operation. |
**To measure the upload data throughput from a Tape Gateway to AWS**
1. Open the CloudWatch console at [https://console.aws.amazon.com/cloudwatch/](https://console.aws.amazon.com/cloudwatch/).
1. Choose the **Metrics** tab.
1. Choose the **StorageGateway: Gateway Metrics** dimension, and find the Tape Gateway that you want to work with.
1. Choose the `CloudBytesUploaded` metric.
1. For **Time Range**, choose a value.
1. Choose the `Sum` statistic.
1. For **Period**, choose a value of 5 minutes or greater.
1. In the resulting time-ordered set of data points, divide each data point by the period (in seconds) to get the throughput at that sample period. For example, if the throughput from the Tape Gateway to AWS is 555,544,576 bytes for a given data point, and the period is 300 seconds, then the approximate throughput would be 1.85 megabytes per second.
**To measure the data latency from a Tape Gateway to AWS**
1. Open the CloudWatch console at [https://console.aws.amazon.com/cloudwatch/](https://console.aws.amazon.com/cloudwatch/).
1. Choose the **Metrics** tab.
1. Choose the **StorageGateway: GatewayMetrics** dimension, and find the Tape Gateway that you want to work with.
1. Choose the `CloudDownloadLatency` 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 latency in milliseconds.
**To set an upper threshold alarm for a Tape Gateway's throughput to AWS**
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. Choose the **StorageGateway: Gateway Metrics** dimension, and find the Tape Gateway that you want to work with.
1. Choose the `CloudBytesUploaded` metric.
1. Define the alarm by defining the alarm state when the `CloudBytesUploaded` metric is greater than or equal to a specified value for a specified time. For example, you can define an alarm state when the `CloudBytesUploaded` metric is greater than 10 megabytes for 60 minutes.
1. Configure the actions to take for the alarm state. For example, you can have an email notification sent to you.
1. Choose **Create Alarm**.
**To set an upper threshold alarm for reading data from AWS**
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. Choose the **StorageGateway: Gateway Metrics** dimension, and find the Tape Gateway that you want to work with.
1. Choose the `CloudDownloadLatency` metric.
1. Define the alarm by defining the alarm state when the `CloudDownloadLatency` metric is greater than or equal to a specified value for a specified time. For example, you can define an alarm state when the `CloudDownloadLatency` is greater than 60,000 milliseconds for greater than 2 hours.
1. Configure the actions to take for the alarm state. For example, you can have an email notification sent to you.
1. Choose **Create Alarm**.