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Question on DAG's RRS feed

  • Question

  • Hi

    I am brushing up my Exchange 2010 knowledge and had some questions on DAG's for which I couldn't find the answer anywhere.

    I understand a DAG is a collection of Mailbox servers that hosts a set of database stores.

    Questions:

    1. Can a mailbox server be a member of more than 1 DAG?

    2. When we create a DAG, we assign an IP address to it. I'm still unsure why we need to do this? What actually connects to the DAG itself, surely all the connections are to the DB's within it?

    3. On a DAG Properties, I see that Network Interfaces are listed. Is this Replication network interfaces or interfaces that wil allow MAPI (client) connections to/from CAS servers?

    4. If a DAG member itself has multiple network interfaces, is it possible to specify which one is used for DAG replication?

     

    Tuesday, August 23, 2011 10:41 PM

Answers

  • 1.  No.

    2.  Because it's the cluster address.  It's required by Windows.  I don't know that anything has to use it, but maybe the CAS does.

    3.  You'll get a list of every network on the server.  If you have multiple networks for, say iSCSI or backups, you may want to exclude those from replication.

    4.  Yes, by excluding all others.  See the link below, particularly the IgnoreNetwork and ReplicationEnabled properties.

    http://technet.microsoft.com/en-us/library/dd298008.aspx


    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    • Proposed as answer by Steve GoodmanMVP Thursday, August 25, 2011 10:24 AM
    • Marked as answer by Jerome Xiong Friday, September 2, 2011 9:09 AM
    Wednesday, August 24, 2011 1:48 AM
    Moderator

All replies

  • 1.  No.

    2.  Because it's the cluster address.  It's required by Windows.  I don't know that anything has to use it, but maybe the CAS does.

    3.  You'll get a list of every network on the server.  If you have multiple networks for, say iSCSI or backups, you may want to exclude those from replication.

    4.  Yes, by excluding all others.  See the link below, particularly the IgnoreNetwork and ReplicationEnabled properties.

    http://technet.microsoft.com/en-us/library/dd298008.aspx


    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    • Proposed as answer by Steve GoodmanMVP Thursday, August 25, 2011 10:24 AM
    • Marked as answer by Jerome Xiong Friday, September 2, 2011 9:09 AM
    Wednesday, August 24, 2011 1:48 AM
    Moderator
  • 2. Many backup programs use the Cluster IP to connect to the DAG and iterate through the stores. The clients themselves do not connect to the DAG IP. In fact, it can be offline and replication and failovers will work just fine.

    The official scoop:

    Windows failover clustering registers the IP addresses for the cluster in the Domain Name System (DNS) when the Network Name resource is brought online. In addition, a cluster network object (CNO) is created in Active Directory. The name, IP addresses and CNO for the cluster are used only internally by the system to secure the DAG and for internal communication purposes. Administrators and end users don't need to interface with or connect to the DAG name or IP address for any reason.

    http://technet.microsoft.com/en-us/library/dd979799.aspx

     

    Friday, August 26, 2011 4:29 AM
    Moderator
  • thank you!
    Friday, August 26, 2011 7:24 AM