Exchange 2010 high availability - Database Availability Groups (DAG) or Vmware HA

Raymond Jansen
Raymond Jansen used Ask the Experts™

Current situation: 1 Exchange 2010 (enterprise) server in datacenter, Windows 2008r2 (enterprise) virtual machine, vmware esxi 4.1.

We wish to implement high availability (with second datacenter).

What would be the best option:
- In new datacenter also Windows 2008r2 virtual machine, vmware esxi 4.1 with DAG
- HA option in Vmware.

So my questions are:
- Which option, and why?
- How to implement?

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BusbarSolutions Architect

the first thing that you will need to do DAG, DAG gives you service availability and data availability so if the OS or the VM itself got an issue DAG will enable you to survive.
just install the VMware in the second datacenter and configure the DAG to stretch across the 2 Data centers. check
If you setup DAG, this will not give you HA I'd rather say it gives you A disaster Recovery for your mailboxdatabases if one were to fail / crash.

Depending on the HA you would need to set the mount time of the other MB database to less than a minute, with using the Default actiovation database policy it will take about 3-5 minutes before the passive mailbox database will mount on your second exchange server that holds the mb role.

Also if your only planning on having one "active" exchange server, I take it youll have the basic three role setup on this one (hub, cas, mb)

Remember to have these roles installed on your second exchange server as well, since no mail flow will be working otherwise in a scenario where your primary exchange server goes down that holds cas / hub and your second exchange server only holds the MB role.

Also depending if your sitting behind a firewall or use a front-end email server, remember to set up correct DNS records / internal ip address of exchange (depending on your network infrastructure)

For further information You can read the answeres I've provided on various setups and requirments regarding HA / DR (and different options)

System Design:

Exchange DAG has specific networking requirement:

DAG options:

If you have further questions I'll be happy to assist,


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