Migration uses CPU, memory, and disk bandwidth. If migration is performed during peak hours, it might take more time than expected or might add a load on the existing jobs. Hence, we recommend you to perform the migration during a scheduled maintenance time or during off-peak hours.
If there are many attachment data to migrate, to optimize the time taken to migrate, select the date range for event data partitions that have attachments. You can migrate the rest of the event data partitions as per your requirement.