Dear all, My company have one customer which running Exchange Server 2010 with Unified Messaging. This customer's premises sometime experience internet intermittent issue and it caused email server can't communicate with outside world. My question is:- May I know is can we implement another offisite exchange server 2010 located at data center, then it will sync with on-premises's exchange server? If yes, what would be the pre-requisite? Design? May I know can we implement Exchange Online as offsite exchange server and sync with on-premises exchange server(IF on-premises running Unified Messaging role?) Thank You Best Regards,Stan

If you put a server in a data centre or other off site location, how does that help? I guess you want users inside to be able to continue to use email during this outage? The data can only exist in one location, otherwise you cannot sync the changes. Perhaps instead you should look at an additional Internet connection so that if the primary goes down the second connection stays in place. The Exchange online system is designed to have some users off site and some on site, not in both locations. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Dear Simon, Thank You for your reply. Yes, I would like to on-premises user to be able to use when internet is outages. I've looked for secondary internet connection and it will up and running soon. However, if whole building is power outages, how can we design a disaster site? Just hope to get the idea for contingency plan. Thank You. Best Regards, Stan

In exchange 2010, you can use database availability group (DAG) for the task Planning for High Availability and Site Resilience Understanding Database Availability Groups James Luo TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Dear James, DAG designed also required to be located at customer's premises. DAG is not our preferences. I am looking for another solution where can have "relay" or offsite exchange server. Thank You.Stan

DAG is about your only option with Exchange. It is possible to have email queue elsewhere for delivery, but that is all it does - queue. It wouldn't allow you access to the email. The issue you have if you use a second solution that isn't Exchange based is how do you get the email in to the server. It doesn't help that you have now changed the requirements. What works for an Internet failure doesn't work for a power outage. You aren't going to get a one size fits all solution. Certainly nothing automated. You could use a DAG, with the datacentre activation options used to control the server coming online. That would allow you to have the internal server working for internal mail during an Internet connection failure, but if you lose the entire site, the remote server is activated. The server would be located in a data centre somewhere. http://technet.microsoft.com/en-us/library/dd979790.aspx If you don't want to use another site, then how are you going to work when you have a power failure? Perhaps you just need a generator. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.