Monitoring cache storage - AWS Storage Gateway

Monitoring cache storage

You can find information following about how to monitor a gateway's cache storage and how to create an alarm so that you get a notification when parameters of the cache pass specified thresholds. Using this alarm, you know when to add cache storage to a gateway.

You only monitor cache storage in the cached volumes architecture. For more information, see How Tape Gateway works.

Item of Interest How to Measure

Total usage of cache

Use the CachePercentUsed and TotalCacheSize metrics with the Average statistic. For example, use the CachePercentUsed with the Average statistic to analyze the cache usage over a period of time.

The TotalCacheSize metric changes only when you add cache to the gateway.

Percent of read requests that are served from the cache

Use the CacheHitPercent metric with the Average statistic.

Typically, you want CacheHitPercent to remain high.

Percent of the cache that is dirty—that is, it contains content that has not been uploaded to AWS

Use the CachePercentDirty metrics with the Average statistic.

Typically, you want CachePercentDirty to remain low.
To measure the percent of a cache that is dirty for a gateway and all its volumes

  1. Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.

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

  3. Choose the CachePercentDirty metric.

  4. For Time Range, choose a value.

  5. Choose the Average statistic.

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

The resulting time-ordered set of data points contains the percentage of the cache that is dirty over the 5 minutes.

To measure the percent of the cache that is dirty for a volume

  1. Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.

  2. Choose the StorageGateway: Volume Metrics dimension, and find the volume that you want to work with.

  3. Choose the CachePercentDirty metric.

  4. For Time Range, choose a value.

  5. Choose the Average statistic.

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

The resulting time-ordered set of data points contains the percentage of the cache that is dirty over the 5 minutes.