The basic question is this: what issues might I encounter if I have an existing Exchange 2010 server and I install the domain controller role on it? This is a small organization (<10 people).
For background as to why I need to do this...
Our network currently has a single domain controller and a single Exchange server that fills all Exchange roles. Bear in mind that I realize that this is not an ideal setup (we should have an additional DC and should have our internal Exchange roles on a different server from the external roles), but with the size of our organization it's very difficult to justify purchasing additional hardware.
Our current online backup solutions (two of the big names; no need to mention them here) support backing up Active Directory data as well as the Exchange database, but in order to do this the backup client must run on the DC and the Exchange server, respectively. Since we only have one server backup license, our current process is to back up all of the other machines and servers to a central location, then allow the backup client to back up this data. However, since the client must run on the DC to back up Active Directory and the Exchange server to back up Exchange, this obviously presents us with a problem.
We also use Windows Server Backup to back up fill images of all of our servers to external hard drives that get swapped out once per week, but we'd like the added security of having our AD and Exchange data current (and not potentially 6 days old).
The solution we're tossing around right now is simply to convert the Exchange 2010 server into another domain controller, which would allow us to back everything up to that machine and grab our files, AD, and Exchange data all at once. What sort of problems might this cause?