Are there any negative ramifications for upgrading my domain and forest from a functional level of 2003 to 2008? My two AD domains controllers are both Server 2008, but I haven't raised the functional level of the domain/forest.
I have about 300 macs bound to the domain. Will their bindings break? Or will I need to rebind for some other reason?
We are of similar size and population. We upgraded to 2008 R2 a couple of three years ago. About the only trouble we had was with our old PowerPC Macs back then. We still had one lab of that hardware on 10.5.8 and well....it didn't seem to work well and Kerberos seemed to break, but we didn't seem to have problems on our 10.6.3 stations. We solved this issue by modernizing that particular lab. It was an old antique PowerPC lab that we simply decided that summer to replace...once everything was on 10.6 or higher, we've had no problems. Hopefully you don't have any Macs of that vintage. All of ours are 10.6.8 or 10.8.4 now.
4th from me -
at the last place I was stationed, we got upgraded from 2003 to 2007 to 2010 in the space of a few months -- figured it out when the certs changed, got told a month after the fact. You're all good.