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AWS Storage Gateway
User Guide (API Version 2013-06-30)

Understanding Storage Gateway Metrics

You can find information following about metrics you can use to monitor your gateways, volumes and file shares.

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.

Topics

    The following table describes the Storage Gateway metrics that you can use to get information about your gateway. The entries in the table are grouped functionally by measure.

    Note

    The reporting period for these metrics is 5 minutes.

    Metric Description Applies To..
    CacheHitPercent

    Percent of application reads served from the cache. The sample is taken at the end of the reporting period.

    Units: Percent

    File, Cached volumes and Tape.

    CachePercentUsed

    Percent use of the gateway's cache storage. The sample is taken at the end of the reporting period.

    Units: Percent

    File, Cached volumes and Tape.

    CachePercentDirty

    Percent of the gateway's cache that has not been persisted to AWS. The sample is taken at the end of the reporting period.

    Units: Percent

    File, Cached volumes and Tape.

    CloudBytesDownloaded

    The total number of compressed bytes that the gateway downloaded from AWS during the reporting period.

    Use this metric with the Sum statistic to measure throughput and with the Samples statistic to measure input/output operations per second (IOPS).

    Units: Bytes

    File, Cached volumes, Stored volumes and Tape.

    CloudDownloadLatency

    The total number of milliseconds spent reading data from AWS during the reporting period.

    Use this metric with the Average statistic to measure latency.

    Units: Milliseconds

    File, Cached volumes, Stored volumes and Tape.

    CloudBytesUploaded

    The total number of compressed bytes that the gateway uploaded to AWS during the reporting period.

    Use this metric with the Sum statistic to measure throughput and with the Samples statistic to measure IOPS.

    Units: Bytes

    File, Cached volumes, Stored volumes and Tape.

    UploadBufferFree

    The total amount of unused space in the gateway's upload buffer. The sample is taken at the end of the reporting period.

    Units: Bytes

    Cached volumes and Tape.

    CacheFree

    The total amount of unused space in the gateway's cache storage. The sample is taken at the end of the reporting period.

    Units: Bytes

    File, Cached volumes, and Tape.

    UploadBufferPercentUsed

    Percent use of the gateway's upload buffer. The sample is taken at the end of the reporting period.

    Units: Percent

    Cached volumes and Tape.

    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.

    Units: Bytes

    Cached volumes and Tape.

    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.

    Units: Bytes

    File, Cached volumes and Tape.

    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.

    Units: Bytes

    File, Cached volumes, Stored volumes and Tape.

    ReadBytes

    The total number of bytes read from your on-premises applications in the reporting period for all volumes in the gateway.

    Use this metric with the Sum statistic to measure throughput and with the Samples statistic to measure IOPS.

    Units: Bytes

    File, Cached volumes, Stored volumes and Tape.

    ReadTime

    The total number of milliseconds spent to do read operations from your on-premises applications in the reporting period for all volumes in the gateway.

    Use this metric with the Average statistic to measure latency.

    Units: Milliseconds

    File, Cached volumes, Stored volumes and Tape.

    TotalCacheSize

    The total size of the cache in bytes. The sample is taken at the end of the reporting period.

    Units: Bytes

    File, Cached volumes, and Tape.

    WriteBytes

    The total number of bytes written to your on-premises applications in the reporting period for all volumes in the gateway.

    Use this metric with the Sum statistic to measure throughput and with the Samples statistic to measure IOPS.

    Units: Bytes

    File, Cached volumes, Stored volumes and Tape.

    WriteTime

    The total number of milliseconds spent to do write operations from your on-premises applications in the reporting period for all volumes in the gateway.

    Use this metric with the Average statistic to measure latency.

    Units: Milliseconds

    File, Cached volumes, Stored volumes and Tape.

    TimeSinceLastRecoveryPoint

    The time since the last available recovery point. For more information, see Your Cached Gateway is Unreachable And You Want to Recover Your Data.

    Units: Seconds

    Cached volumes and Stored volumes.

    WorkingStorageFree

    The total amount of unused space in the gateway's working storage. The sample is taken at the end of the reporting period.

    Units: Bytes

    Stored volumes only.

    WorkingStoragePercentUsed

    Percent use of the gateway's upload buffer. The sample is taken at the end of the reporting period.

    Units: Percent

    Stored volumes only.

    WorkingStorageUsed

    The total number of bytes being used in the gateway's upload buffer. The sample is taken at the end of the reporting period.

    Units: Bytes

    Stored volumes only.

    Volume Metrics

    You can find information following about the Storage Gateway metrics that cover a volume of a gateway. Each volume of a gateway has a set of metrics associated with it. Note that some volume-specific metrics have the same name as certain gateway-specific metrics. These metrics represent the same kinds of measurements but are scoped to the volume instead of the gateway. You must always specify whether you want to work with either a gateway or a volume metric before working with a metric. Specifically, when working with volume metrics, you must specify the VolumeId that identifies the storage volume for which you are interested in viewing metrics. For more information, see Using Amazon CloudWatch Metrics.

    The following table describes the Storage Gateway metrics that you can use to get information about your storage volumes.

    Metric Description Cached volumes Stored volumes
    CacheHitPercent

    Percent of application read operations from the volume that are served from cache. The sample is taken at the end of the reporting period.

    When there are no application read operations from the volume, this metric reports 100 percent.

    Units: Percent

    yes no
    CachePercentDirty

    The volume's contribution to the overall percentage of the gateway's cache that has not been 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 has not been persisted to AWS. For more information, see Gateway Metrics.

    Units: Percent

    yes no
    CachePercentUsed

    The volume's contribution to the overall percent use of the gateway's cache storage. The sample is taken at the end of the reporting period.

    Use the CachePercentUsed metric of the gateway to view overall percent use of the gateway's cache storage. For more information, see Gateway Metrics.

    Units: Percent

    yes no
    ReadBytes

    The total number of bytes read from 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

    yes yes
    ReadTime

    The total number of milliseconds spent to do read operations from your on-premises applications in the reporting period.

    Use this metric with the Average statistic to measure latency.

    Units: Milliseconds

    yes yes
    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

    yes yes
    WriteTime

    The total number of milliseconds spent to do write operations from your on-premises applications in the reporting period.

    Use this metric with the Average statistic to measure latency.

    Units: Milliseconds

    yes yes
    QueuedWrites

    The number of bytes waiting to be written to AWS, sampled at the end of the reporting period.

    Units: Bytes

    yes yes

    File Share Metrics

    You can find information following about the Storage Gateway metrics that cover file shares. Each file share has a set of metrics associated with it. Note that some file share-specific metrics have the same name as certain gateway-specific metrics. These metrics represent the same kinds of measurements but are scoped to the file share instead. You must always specify whether you want to work with either a gateway or a file share metric before working with a metric. Specifically, when working with file share metrics, you must specify the File share ID that identifies the file share for which you are interested in viewing metrics. For more information, see Using Amazon CloudWatch Metrics.

    The following table describes the Storage Gateway metrics that you can use to get information about your file shares.

    Metric Description
    CacheHitPercent

    Percent of application read operations from the file shares that are served from cache. The sample is taken at the end of the reporting period.

    When there are no application read operations from the file share, this metric reports 100 percent.

    Units: Percent

    CachePercentDirty

    The file share's contribution to the overall percentage of the gateway's cache that has not been 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 has not been persisted to AWS. For more information, see Gateway Metrics.

    Units: Percent

    CachePercentUsed

    The file share's contribution to the overall percent use of the gateway's cache storage. The sample is taken at the end of the reporting period.

    Use the CachePercentUsed metric of the gateway to view overall percent use of the gateway's cache storage. For more information, see Gateway Metrics.

    Units: Percent

    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

    ReadTime

    The total number of milliseconds spent to do read operations from your on-premises applications in the reporting period.

    Use this metric with the Average statistic to measure latency.

    Units: Milliseconds

    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

    WriteTime

    The total number of milliseconds spent to do write operations from your on-premises applications in the reporting period.

    Use this metric with the Average statistic to measure latency.

    Units: Milliseconds