I have a small customer running Exchange 2010 who are looking for some high availability. They are a small shop with 30 users. However they can not work when Exchange goes down. It is their email program, their calendars and they integrate document management and time tracking into Outlook.
They essentially come to a standstill if Exchange goes offline, they are highly reliant on technology. But because of the small size the budget is not unlimited. So I need some suggestions for Exchange high availability on a budget.
The software is Exchange 2010 running on 2008 R2 Standard at the moment. That rules out a DAG so changes have to be made.
I believe the options are to keep 2010 but upgrade 2008 R2 to enterprise so we can do DAG's. Or upgrade to 2012 R2 to do DAG's. Keeping Exchange at 2010 saves some money and 2013 does not really have any features they need unless there is a compelling feature related to high availability.
The hardware currently is a number of HP servers but that is going to be upgraded to bigger HP servers running either vmware or hyper-v so I can have more flexibility with adding servers. All storage will be local storage, no SAN here.
So what is the minimum number of copies of Exchange I need to make this highly available?
My thoughts are at least 3. Two running the MBX role in a DAG and one acting as the CAS server. But if the CAS server goes down it won't matter that the DAG is up. So I guess it's 4 servers. Two running MBX in a DAG and 2 running CAS in an array.
Or is there a way to have just 2 servers each of them running all roles? They act as a DAG and as a CAS array. Not sure that is possible.
Any other scenarios here that make more sense or suggestions on how to make these two options work?
Any help is appreciated.