A start-up firm is using the Amazon S3 file gateway to store on-premises data to AWS securely. The Sysops Team needs to ensure that all cache data is properly uploaded to AWS so that in the event of a disaster there is no impact due to data loss. Operations Lead needs you to share the percentage of data that is not uploaded to AWS.
Which Amazon CloudWatch metric can be checked for this purpose?

Answer options:

A.CacheMissPercent
B.CacheHitPercent
C.CachePercentDirty
D.CachePercentUsed

Correct Answer: C
CachePercentDirty is an Amazon CloudWatch metric for Amazon S3 File Gateway which provides a percentage of the data not uploaded to AWS from local Cache. This metric value should be near to zero to ensure all cache data is properly uploaded to AWS.
Option A is incorrect as CacheMissPercent is an invalid Amazon CloudWatch metric for the storage gateway.
Option B is incorrect as CacheHitPercent will provide a percentage of a read request handled by the cache. This will not provide details of the content that is uploaded to AWS.
Option D is incorrect as CachePercentUsed will provide the percentage of the cache used. It would not provide details of the content that is uploaded to AWS.
For more information on monitoring performance with Amazon Storage Gateway, refer to the following URL,
https://docs.aws.amazon.com/storagegateway/latest/userguide/Main_monitoring-gateways-common.html#PerfCache-common