Upgrading from SBS 2008 and Exchange Server 2007 and Adding Modest Failover Protection

Question

I haven't seen anyone describe this scenario, so maybe it can't be done, but it seems it should work. Can someone either confirm this is viable or set me straight and tell me it's not wise (and if not, why not).
I currently have SBS 2008 (2008 Server + Exchange Server 2007 + some other components). I use redirected folders so all my user data is stored primarily on the server, and then sync'd with their local harddrives for roaming use and as an additional
backup precaution. I want to upgrade to a modern version of Exchange (don't care too much about the underlying server OS, but seems like a good time to upgrade everything). I also want to improve the reliability for rapid recovery in the event of a system
failure. I have always felt nervous with SBS because it only runs on a single server.
My plan is:
Install Windows Server 2012 Standard on a new server machine
Join that new server to the existing SBS domain and sync the users, etc.
Install Exchange Server 2013 on the new 2012 Server
Migrate the existing Exchange data and account info to the new server
Demote the SBS Server and promote the new server to primary DC
Reformat the old SBS server and install Windows Server 2012 on it too, and join it to the domain as a second DC
Set up DFS Replication and keep all my user data folders between the two servers (so if one server fails, the other can take over, just not automatically like with a cluster)
Install Exchange Server 2013 on the reformatted 2012 Server box (so second instance on the domain) and set it up to sync with the first Exchange Server 2013 via DAG (so if either computer crashes, the other can take over for both Exchange Server and file
services)
Wouldn't that give me a complete slow-response failover system without the need for setting up a cluster (I know a cluster would provide instant failover protection, but I don't need that kind of speed - a manual switchover in the rare event of a server
failure is acceptable for us)? I could do this using cheap hardware for each server, because unless both servers fail at the same time, clients can point to the other server. And because it's not a formal cluster, I don't need to buy anything for a shared
SAN. This seems like such an obvious more cost-effective solution for a small network, I don't understand why this isn't a common approach, which makes me wonder if there is some reason it won't work.
Any suggestions or feedback? Are Redirected Folders still recommended for users on a Server 2012-based domain?
Thanks,
Colin
Colin

Answer 1

Ed, thanks again for your help. OK, so here's my updated plan (I realize I should probably check on some of these pieces on the Server group, instead of this Exchange group).
Constraints/objectives:
None of the machines are truly server grade hardware, but only 5 people on the network, so performance is generally not an issue, unless a given server is just pegged on CPU or HD due to its own internal maintenance tasks and can't respond to user requests.
Haven't seen any problems, since upgrading server from 4GB RAM to 8GB a few years ago.
Not going to buy any new hardware at this time, but do have several unused consumer-grade computers I can deploy as wimpy or moderate servers.
Main issue is to limit repair time in the event of a system failure (instant failover is not required, but want to be able to restore network functions within less than 24 hours in the event of a hardware failure) and minimize time spent on IT
maintenance.
Because of light IT maintenance (not anyone's primary job and we're too small to justify a dedicated IT person or to pay for outside help), almost every touch takes me research and time to re-learn what I haven't done in weeks, months, or years -- so also
want to keep all IT tasks as simple as possible.
We philosophically want to invest now for the next 5 years and avoid ongoing cloud fees (so zero interest in Windows Server Essentials with Exchange Online)
A little nervous about using VM's, just because I never have before, but I do respect that's probably the right way to do many of these things...
Currently I have SBS 2008 (Windows Server 2008 R2, Exchange Server 2007, WSUS 3, all with latest SP's, also includes SharePoint and other stuff, but I don't really care about most of it) on a single 8GB consumer grade system, which functions as a file
server and Exchange server. We use Redirected Folders and Offline files for all users, which works great for us and provides additional file redundancy (if server goes down, all of each user's files are also on their own machine and they can even continue
to work just fine w/o the server, losing only ability to send and receive e-mail). It has been sufficient, but I want to upgrade our version of Exchange and I am nervous that if that current one server fails, it would take me a long time to restore everything
from backup, easily many days, especially if I need to buy any replacement hardware. It is RAID1, so a single drive failure is easy to handle, but that's the only hardware redundancy for the current server.
New Plan:
Install Windows Server 2012 R2 Standard on a new modest machine (16GBR RAM, Core i7, 1TB RAID1 (may upgrade to 3 or 4 TB), 256 GB SSD boot drive, this had been my old personal computer)
Join that new server to the existing SBS domain (2008 R2/Exchange 2007), make it a DC, sync the users, etc.
Install Windows Server 2012 R2 Standard on a wimpy computer (4GB RAM Core i3 processor), leave it as a member server
Install Exchange Server 2013 on the wimpy new 2012 R2 Server (and nothing else, this will be dedicated to Exchange to make the most of such a wimpy machine)
Migrate the existing Exchange data from the old SBS Exchange 2007 server and account info to the new server
(or should I just create new accounts and copy the data from the user end through Outlook -- is that safer and cleaner than attempting any kind of server-level Exchange data migration?)
Demote the old SBS Server and promote the new 16GB server to primary DC. Now it's OK to take the old SBS server off the network.
Reformat the old SBS server and install Windows Server 2012 R2 on it too, and join it to the domain as a second DC (and possibly DCPROMO it to be the main server)
Install Exchange Server 2013 in a VM on the reformatted 2012 R2 Server box (so second instance on the domain for Exchange redundancy) and set it up to sync with the first Exchange Server 2013 via DAG OR set up another physical wimpy member server and install
it there. In any case, do NOT install Exchange directly on either DC.
Set up DFS Replication or a Failover Cluster (still need to research this, but I had planned on DFS, thinking Cluster required shared drive, but Ed corrected me on this) between the two DC's for redirected files and keep all my user data folders between
the two servers. We don't need automatic failover, like with a cluster, a manual switch would be acceptable, but if no additional cost or risk to clustering the two DC's, then the auto-failover protection that provides would be better than DFS.
I think this incorporates all of your points, Ed. Does this sound right now? What's your advice on #5 (how to best migrate user data)?
Thanks so much for all your help,
Colin