Certkiller .com has a main office and branch office in another city. You are assigned to deploy and implement a Read-only Domain Controller （RODC） at the branch office. You deploy a RODC that runs Windows Server 2008. 
What should you do to ensure that the users at the branch office can log on to the domain using RODC（）

Critical services are running on CKD20， a domain controller. You have completed restructuring the organizational unit hierarchy for the domain and deleted the needless objects. 
What would you do to perform an offline defragmentation of the Active Directory database on CKD20 while ensuring that the critical services remain online（）