Toll Free: +1 888 900 4529
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Toll Free: +44 800 088 5522 
Toll Free: +1 888 900 4529
| Toll Free: +44 800 088 5522 The Witness Server can be defined as the addition server, which is not the member of the DAG and stores the Active copy of the Database. It acts as an observer and guarantees that Quorum is preserved in the Cluster.
It is always installed on the Hub Transport Server. It does not have Mail Server and it is the reason why it is not considered as the part of the DAG.It should be the member of Same Active Directory forest as DAG.
In case if does not indicate the witness server then it will search the Hub Transport Server which does not have a mail server and will configure it as the witness server.
Witness Server plays an important role in the Exchange 2010 DAG: The Witness Server helps a lot in quick and safe recovering of the DAG from an unexpected failure. It also guarantees that a Quorum is preserved in the cluster.
Witness Server stores the active copy of the Database: The active copy of the witness server is stored in the Witness Server. This active copy of the witness server can be used in case of the corruption of the database.
The witness server simply supports the automatic failover: The Witness server helps a lot in recovering from the failover. It supports Automatic failover by verifying that whether the principal server is up and functioning. If the principal server is down it will try to recover it from the unexpected failure.
The witness server and its directory are used for the quorum purposes: Quorum can be defined as the number of active elements that must be online for that cluster to continue running. The witness server and its directory are used for the quorum purposes when there are even number of members in the DAG.
Witness Server is one of the most important component in the DAG. It helps in protecting the DAG from the Unpredictable failure. Within the 30 seconds it assigns a fresh copy to the DAG so that it can carry out the process.
Witness server is the best solution to perform the recovery operation of the DAG. It helps a lot to make the server active if anything wrong happens. But sometimes active data present in the Witness server gets Corrupted and it fails to overcome the issue of the DAG. In that case we need to use the external solution to resolve the issue.
The above discussion will help you to understand What is Witness Server, its uses and its importance in the DAG. If you have any question related to the topic, please comment here, we will sort out your query as soon as possible.
