Have a customer with 100 sites ( and 110 controllers ). Will be taking them from MCD 4 with OpsMan to MCD 5 with RDN sync. The will need SDS between all the sites. Does anyone have experience with something of this size and what do I need to take into consideration in programming the systems for SDS. In a "using SDS doc" I found in MOL it says it is not recommended to have more then 20 controllers in a Admin group. So that means "reach through" is going to be very fragmented but we can live with that, but does that mean we need to set SDS to only share to admin groups or can we still let it share to the cluster. Thanks.

I'd tell you a UDP joke but I'm afraid you won't get it. TCP jokes are the best because you always get them.

Hello
Make sure you continue to use Enterprise Manager. That will give you single pane access into all the different MCD systems. It will also give you a single place with all your Users and Devices being easily shown. When you group your systems into Admin Groups, put them together logically, either geographically or technically, eg you could group User Controllers together in 1 Admin Group and Trunking Gateways in a different group. When using Enterprise Manager, Admin Groups become mush less important as all the alarming information and back-ups are scheduled from Enterprise Manager and it gives you direct access into all the different MCD nodes through your specific user login. Make sure you set-up the correct access levels you want for each user in the MCD network as the usernames are all now synchronised between MCD and Enterprise Manager.
And, when you migrate to GDM, do so from MCD 4.0 SP 4.

I migrated a network of 30 elements and chopped them up into geographical admin groups. I would def look to migrate from 4.0 SP4 and this is what Mitel strongly recommends as well. Looks like you will have a lot of migration prechecks and database cleansing to do!! My tidy up took me approx 2 weeks with a tel dir of just under 9,500. Good luck!