Author: Shelly Bhardwaj

Database Availability Group (DAG) setup in Exchange Server provides full protection and recovery in case of database, network, or server failure. In a DAG, you can have up to 16 mailbox servers hosting a set of databases. This helps provide automatic, database-level recovery in case something happens. 

Sometimes, situations arise when you need to split the Database Availability Group (DAG) and move the mailboxes from one availability group to another. Some common situations are:

In Exchange Server, database backup is essential to prevent loss of data in case of disaster or unforeseen incidents, such as power outage, server failure, natural calamities, etc. At the same time, it is also important to decide on the data backup method as it is not practical to take a full data backup every time, considering the resources needed, the time to take backups daily, and the cost. So, you can choose between incremental and differential backup methods for taking frequent and regular database backups in Exchange Server.

In this article, we will discuss the differences between incremental and differential backup methods to help you decide which one to choose based on your needs. 

Ransomware attacks on on-premises Exchange Servers are quite common as they store sensitive and confidential information and business data. The attackers often exploit vulnerabilities to gain access to the organization's network and steal or encrypt data for ransom.  

Even if attackers do not succeed in encrypting the data, they may leave a backdoor or cause other damage that can leave your server unusable or cause permanent data loss. That's why it's important to have a disaster recovery plan or recovery strategy ready to deal with such critical situations.

Witness Server and Witness Directory are the most critical components of the Database Availability Group (DAG). DAG requires Witness Server or File Share Witness (FSW) and Directory to maintain the Quorum. In case of Witness Server failure, the Quorum is no longer maintained, leading to inconsistent DAG. In addition, the cluster may no longer respond or work, leading to downtimes if a disaster strikes.

However, you can change the Witness Server and Witness Directory to maintain the Quorum and ensure high availability when the Witness Server has failed, is unavailable, or does not boot.

Administrators must put the Exchange Server in maintenance mode while updating and making changes to the server to avoid data loss or other issues. If the changes or any security/cumulative updates are applied to the server without putting the server into maintenance mode, it can lead to database corruption or server failure.

In this article, we discuss the Exchange Maintenance Mode, its importance, and the steps to put the Exchange Server into maintenance mode. We also mention steps to disable maintenance mode once the server update or upgrade is completed.