I'm tying to used below Graph api call .This api call saying, period 'specifies the length of time over which the report is aggregated. The supported values for {period_value} are: D7, D30, D90, and D180. These values follow the format Dn where n represents the number of days over which the report is aggregated.' I didn't get why aggregating rather than give mailboxsize or used storage until the reporting day. Is there any possible way to get storage size of each user?
GET https://graph.microsoft.com/v1.0/reports/getMailboxUsageDetail(period='D7')