i need some information regarding DAG replication issue. In my environment there is two mailbox server. One DC and another in DR site. The connectivity between DC and DR site is VPN. Bandwidth is one MB. But in VPN connection have ping loss. The ping loss rate 1-2%. In my environment twodatabase. one is single and another is under the dag member. when i move mailbox from single to dag database the move rate is so slow and sometimes database going to dismount. I think its happened as because connectivity issue. 

Can you please suggest the details about dag replication. I need to know that: what is dag replication data rate? also the acceptable rate of ping loss and How much rate connectivity between DAG Heartbeat connection.

Please suggest as soon as possible.

Thanks,

Parvez

Please suggest as soon as possible.

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Hi Parvez,

From your description, I would like to clarify the following things:

1. It is not recommended to install Exchange server on DC.

2. The witness server is needed when there's an even number of members in the DAG. Based on your case, you need a file share witness server.

3. The DAG replication rate depends on the replication traffic.

4. By default, heartbeat frequency (subnet delay) is 1000ms for both local and remote subnets. When a node misses 5 heartbeats (subnet threshold) another nod within your DAG cluster will initiate a failover.

What's more, here are some helpful threads for your reference.

Planning for High Availability and Site Resilience

http://technet.microsoft.com/en-us/library/dd638104(v=exchg.150).aspx

Exchange 2010: Collapsing DAG Networks

http://blogs.technet.com/b/timmcmic/archive/2011/09/26/exchange-2010-collapsing-dag-networks.aspx

Hope my clarification is helpful.

Best regards,
Amy

Hi Parvez,

From your description, I would like to clarify the following things:

1. It is not recommended to install Exchange server on DC.

2. The witness server is needed when there's an even number of members in the DAG. Based on your case, you need a file share witness server.

3. The DAG replication rate depends on the replication traffic.

4. By default, heartbeat frequency (subnet delay) is 1000ms for both local and remote subnets. When a node misses 5 heartbeats (subnet threshold) another nod within your DAG cluster will initiate a failover.

What's more, here are some helpful threads for your reference.

Planning for High Availability and Site Resilience

http://technet.microsoft.com/en-us/library/dd638104(v=exchg.150).aspx

Exchange 2010: Collapsing DAG Networks

http://blogs.technet.com/b/timmcmic/archive/2011/09/26/exchange-2010-collapsing-dag-networks.aspx

Hope my clarification is helpful.

Best regards,
Amy

Hello,

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