How to extend AD schema for Exchange

Question

Hi,
Please can someone help me understand the process for extending AD schema for Exchange?
I’m concerned because there are some cautions noted generally in the process so i’m looking for best practice to ensure extending in a safe and smooth manor.
Bit of background on our environment - 
Moving to Office365 in a hybrid environment, never used Microsoft products for email. 
New On-prem AD Physical DC, 2012 Server with DirSync to Azure/ O365
OU’s populated with objects.
Would like to manage users and distribution groups from within AD on-prem.
Many thanks,
Leo.

Answer 1

It is recommended to have at least two DC/GC servers for HA.
We are using Office 365 too for 65k + and we do have Powershell scripts to make the attribute changes and identify users with missing or incorrect messaging attributes. So, you might think about using Powershell scripts too.
65K? That's the largest I've heard yet! Are you in an educational environment? That's what I understand and should have pointed out. We are a university and the first to use O365 consolidating Google, Notes and Mirapoint active mailboxes. We still
haven't touched Alumni, which are on Google. That would take us to the 75k level, but that discussion is on a backburner.
Ace Fekay
MVP, MCT, MCSE 2012, MCITP EA & MCTS Windows 2008/R2, Exchange 2013, 2010 EA & 2007, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP - Directory Services
Complete List of Technical Blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php
This posting is provided AS-IS with no warranties or guarantees and confers no rights.