Nearly two years ago, I presented a session called High Availability Design Considerations at TechEd North America 2010. During my session I described the changes we were making around how MAPI con...
Updated Jul 01, 2019
Version 2.0
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@Chris - Great questions. So you are correct that whenever a cross-site database *over occurs (whether a controlled or uncontrolled scenario) that the Outlook user will be interrupted and require restarting Outlook. If you perceive this is an impactful, you can set AllowCrossSiteRPCClientAccess to $true and ignore the situation. I don't have any specific bandwidth data to give you (you could use Neil's Bandwidth Calculator to get an idea - http://blogs.technet.com/b/exchange/archive/2012/03/09/exchange-client-network-bandwidth-calculator-beta2.aspx); I will point out that Outlook RPC is more resilient to network conditions than CAS to MBX RPC.
As for datacenter activations, no I do not advise using AllowCrossSiteRPCClientAccess to control the Outlook clients. Continue to use our prescribed guidance which is to move the DNS records. This ensures *all* clients are not impacted by the datacenter activation (as they will all continue to use the same namespace and not require reconfiguration).
Ross