The following is the Active Directory health checklist:

• Review connection status between domain controllers
• If the organization has a monitoring system, review the reports and latest events about domain controllers, AD DS roles, replication health, and DNS services
• Review the latest backup reports
• Review DNS issues and events
• Review Active Directory domain controller's health
• Test Active Directory replications
• Review Active Directory logs to find any re-occurrence issues
• Review the existing domain controller's performance
• Review bandwidth utilization between site links