Understanding CloudWatch alarms - Amazon Storage Gateway
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Understanding CloudWatch alarms

CloudWatch alarms monitor information about your gateway based on metrics and expressions. You can add CloudWatch alarms for your gateway and view their statuses in the Storage Gateway console. For more information about the metrics that are used to monitor FSx File Gateway, see Understanding gateway metrics and Understanding file system metrics. For each alarm, you specify conditions that will activate its ALARM state. Alarm status indicators in the Storage Gateway console turn red when in the ALARM state, making it easier for you to monitor status proactively. You can configure alarms to invoke actions automatically based on sustained changes in state. For more information about CloudWatch alarms, see Using Amazon CloudWatch alarms in the Amazon CloudWatch User Guide.


If you don't have permission to view CloudWatch, you can't view the alarms.

For each activated gateway, we recommend that you create the following CloudWatch alarms:

  • High IO wait: IoWaitpercent >= 20 for 3 datapoints in 15 minutes

  • Cache percent dirty: CachePercentDirty > 80 for 4 datapoints within 20 minutes

  • Files failing upload: FilesFailingUpload >= 1 for 1 datapoint within 5 minutes

  • File system error: FileSystem-ERROR >= 1 for 1 datapoint within 5 minutes

For gateways on VMware host platforms that are part of a VMware High Availability cluster, we also recommend these additional CloudWatch alarms:

  • Availability notifications: AvailabilityNotifications >= 1 for 1 datapoints within 5 minutes

  • Health notifications: HealthNotifications >= 1 for 1 datapoints within 5 minutes


    You can set a health notification alarm only if the gateway had a previous health notification in CloudWatch.

The following table describes CloudWatch alarm states.

State Description


The metric or expression is within the defined threshold.


The metric or expression is outside of the defined threshold.

Insufficient data

The alarm has just started, the metric is not available, or not enough data is available for the metric to determine the alarm state.


No alarms are created for the gateway. To create a new alarm, see Creating a custom CloudWatch alarm for your gateway.


The state of the alarm is unknown. Choose Unavailable to view error information in the Monitoring tab.