Hi ,

Could you please let me know if i can built exchange 2010 DAG with one server each site ( primary site & DR site ) with fail over.

each site only have 1 server with all

Yes, you can build a two node DAG however you will need a third server to act as a witness. This third server can either be a File Server or on Azure if you have a DC on Azure and depending on which site you place it you will likely need an alternate witness to be deployed in the opposite datacenter.

If you are only looking for two notes have you thought about O365?  It may be good solution for you. 

More Info

Planning for High Availability and Site Resilience
https://technet.microsoft.com/en-us/library/dd638104(v=exchg.141).aspx

Create a Database Availability Group
https://technet.microsoft.com/en-us/library/dd351172(v=exchg.141).aspx

High Availability and Site Resilience
https://technet.microsoft.com/en-us/library/dd638121(v=exchg.141).aspx

Welcome to Office 365https://support.office.com/en-us/article/Welcome-to-Office-365-da78ee2b-ffe7-44af-b6e9-0d1d5ea99adb?CorrelationId=ba09ef38-fdd9-44f8-8cd3-2e4df9203ebb&ui=en-US&rs=en-US&ad=US

Learn your way around Office 365 for businesshttps://support.office.com/en-us/article/Learn-your-way-around-Office-365-for-business-9b7306d3-8d61-4794-bb6f-6520f65956d9

ThanksScott Feltmann,

I was thinking about office 365 but unfortunately management not ready ,

so I need below things

DR Site

1- ad\dns

2- one exchange 2010 with all role

3- witness

Primary location only having

1- ad\dns

2-exchange 2010 having all role .

thats it right ?

Hi satya,

The witness server for the DAG should be located in the primary datacenter. Generally, the primary datacenter is the datacenter containing the majority of the user population. Using a witness server in the primary datacenter enables continued functionality for the majority of the user population in the event of a wide area network (WAN) outage.

If a WAN outage occurs, only the primary datacenter retains service because it contains the majority of the voters. The datacenter with the minority of voters loses majority, and the DAG members in that datacenter lose quorum and go offline.

Best regards,

Hi Satya11,

You will need a witness and an alternate witness.  The primary Witness will be in the primary datacenter while the alternate witness will be in the DR datacenter. 

Yes, you will need Active Directory and DNS in both datacenters where Exchange will reside.  With the DC/DNS exchange will not function and your mail environment will have issues. 

As Niko pointed out the datacenter with the primary witness enabled will remain online in the event of a WAN failure, however in the event of a site failure and you need to bring DR online that is where the alternate file share witness will be required.  You will want to build some good DR documentation that talks about the procedure for failing over to the DR datacenter or you can leverage the tool noted here:

Exchange 2010 datacenter switchover tool now available
http://blogs.technet.com/b/exchange/archive/2012/10/19/exchange-2010-datacenter-switchover-troubleshooter-now-available.aspx

So based on what you asked you will have in the DR Site

• AD/DNS
• Exchange 2010 multirole
• Alternate Witness

In the Primary site you will have:

• AD/DNS
• Exchange 2010 multirole
• Primary Witness

don't forget the idea around mail routing as well.  You could establish two MX Records for mail routing weighted so that mail will travel to the primary site first and then a higher weight so it will go to DR in the event of a failure.  I would also recommend to stage DR URLs in the event of a failure so users can access their mailboxes until you can switch over the DNS name spaces to point to DR with your primary URL namespace. 

There is a lot of planning that has to go in DR and you can use the information I noted above:

Planning for High Availability and Site Resilience
https://technet.microsoft.com/en-us/library/dd638104(v=exchg.141).aspx

Also, since you only have two copies of your database I would encourage you to maintain a backup solution for Exchange 2010.  With only two copies of the database you run the risk of being at a single copy in the event a server should fail. 

Hope this helps.

Yes, Exchange 2010 SP1 and later supports this scenario.

As you have two AD sites and I assume you are running Exchange 2010 SP1 or later, you should seriously consider enabling DAC (Datacenter Activation Coordination) as well.

You can find more info about DAC here.

Step by Step Screencasts and Video Tutorials