Delete database in a hybrid environment with Office 365

Hi all, In order to get more free space in my Exchange Server 2010, I was thinking to delete a database after move all mailboxes that are in this database to office 365.

Is this a good idea?Because deleting logs is not enough for me, I need more free space. Which impact I will have if I do it after move all mailbox from this database to cloud?

Thanks so much!