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Large multi-site Unity install


We're in the design phase for a 4 site 8,000 user Unity VM install. The environment is Lotus w/ W2000 AD. All sites are interconnected with high speed WAN links of T1 or greater. My question is can we integrate Unity with the existing Domain, update the schema, install Exchange 2000 external message store servers for each site, and utilize existing Global catalog servers while not causing issues with the current Lotus email system? Keep in mind this is a VM only install. Two major benefits of this design would be the use of existing Global Catalog servers and access to Active Assistant would be simplified.

If this isn't possible I would assume we'd need to create a Unity domain and add every Unity server and external Exchange 2000 message store to the domain and possibly have additional separate DCs acting as Global Catalog servers at each of the sites.

Any design ideas or best practices for large installs would be greatly appreciated.


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Re: Large multi-site Unity install

Obviously it would depend on how many users at each site, but ideally you should create a parallel domain for voicemail. You could utilize the existing domain - since there is no relation between AD and Notes. Because of the intrusiveness to the domain, though, I wouldn't recommend it. I have done a good amount of Unity installs on Exchange and recently with Domino. If you're looking for some help, let me know. I can be reached at my email -


Re: Large multi-site Unity install

I respectfully disagree with Steve on the second domain idea. I’m not trying to be argumentative so I hope there is no offence taken.

I believe very strongly that using the existing domain is your best option. I can't think of a single advantage to having a second domain whether it's a child in the same forest or in a new forest altogether. If you plan to move forward with the single domain you will want to check out this white paper:

Also, you want to ensure that you have adequate DC/GC resources at each site. Unity doesn't add much load to the DC/GCs however Exchange 2000 does. I would recommend at least 2 GCs per site which you might already have.

Steve, if I am unaware of a disadvantage please point it out.

Hope this helps,


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