Understanding gateway metrics

For the discussion in this topic, we define gateway metrics as metrics that are scoped to the gateway—that is, they measure something about the gateway. Because a gateway contains one or more volumes, a gateway-specific metric is representative of all volumes on the gateway. For example, the CloudBytesUploaded metric is the total number of bytes that the gateway sent to the cloud during the reporting period. This metric includes the activity of all the volumes on the gateway.

When working with gateway metric data, you specify the unique identification of the gateway that you are interested in viewing metrics for. To do this, you specify both the GatewayId and the GatewayName values. When you want to work with metric for a gateway, you specify the gateway dimension in the metrics namespace, which distinguishes a gateway-specific metric from a volume-specific metric. For more information, see Using Amazon CloudWatch Metrics.

Note

Some metrics return data points only when new data has been generated during the most recent monitoring period.

Metric	Description
AvailabilityNotifications	Number of availability-related health notifications generated by the gateway. Use this metric with the Sum statistic to observe whether the gateway is experiencing any availability-related events. For details about the events, check your configured CloudWatch log group. Unit: Number
CacheHitPercent	Percent of application reads served from the cache. The sample is taken at the end of the reporting period. Unit: Percent
CacheUsed	The total number of bytes being used in the gateway's cache storage. The sample is taken at the end of the reporting period. Unit: Bytes
IoWaitPercent	Percent of time that the gateway is waiting on a response from the local disk. Unit: Percent
MemTotalBytes	Amount of RAM provisioned to the gateway VM, in bytes. Unit: Bytes
MemUsedBytes	Amount of RAM currently in use by the gateway VM, in bytes. Unit: Bytes
QueuedWrites	The number of bytes waiting to be written to AWS, sampled at the end of the reporting period for all volumes in the gateway. These bytes are kept in your gateway's working storage. Unit: Bytes
TotalCacheSize	The total size of the cache in bytes. The sample is taken at the end of the reporting period. Unit: Bytes
UploadBufferPercentUsed	Percent use of the gateway's upload buffer. The sample is taken at the end of the reporting period. Unit: Percent
UploadBufferUsed	The total number of bytes being used in the gateway's upload buffer. The sample is taken at the end of the reporting period. Unit: Bytes
UserCpuPercent	Percent of CPU time spent on gateway processing, averaged across all cores. Unit: Percent

Dimensions for Storage Gateway metrics

The CloudWatch namespace for the Storage Gateway service is AWS/StorageGateway. Data is available automatically in 5-minute periods at no charge.

Dimension

Description

GatewayId, GatewayName

These dimensions filter the data that you request to gateway-specific metrics. You can identify a gateway to work by the value for GatewayId or GatewayName. If the name of your gateway was different for the time range that you are interested in viewing metrics, use the GatewayId. Throughput and latency data of a gateway is based on all the volumes for the gateway. For information about working with gateway metrics, see Measuring Performance Between Your Gateway and AWS.