Monitor EFS Cost and Usage filter rules for using boto3

Hi everyone,

I'm trying to monitor the EFS usage of a specific drive with the boto3 get_cost_and_usage. However, the return value is more than twice as large as I would expecy from my own bill and the data stored on EFS.

The function in question is:

resources = client.get_cost_and_usage(
    TimePeriod={
        'Start': start_time,
        'End': end_time
    },
    Filter=filter_rules,
    Granularity='DAILY',
    Metrics=['UsageQuantity', 'UnblendedCost']
)

With the filter rules:

[ { 'Key': 'Customer', 'Values': ['customer_id'], 'MatchOptions': ['EQUALS'] } ]

The EFS filesystem has the tag Customer=customer_id assigned.

Hence, the question is: what are the correct filter rules to monitor the usage of EFS in GIB/month?

Thank you in advance.