We are planning a migration from our current EV.cloud tenant to Mimecast archiving. As per company policy we're only required to migrate 7 years worth of emails, however at various stages in the last 7 years, data has been ingested into EV.cloud from the now decommisioned EV on-premise.
Reports against the last 7 years worth of data yields the ingested components as well, which contains data that is mostly outside the 7 year scope and not required.
Is there a method to query just the true size of data for the 7 year period?
I've highlighted the years in which data was ingested in provided screenshot.