As a small but significant follow up to my UPA session at the SharePoint Conference in Anaheim last month, is that yesterday we pushed out an update to the Database types and descriptions article on TechNet to finally detail that synchronous mirroring of the Social database IS 100% supported.
As already detailed in this document, the Profile database already supported synchronous mirroring. That leaves the Sync database, which if you were paying attention in the session we really don’t care about in terms of “HA” or “DR”.
Not perfect by a long shot but you can now officially do what many customers have already done successfully in production for very large deployments, and implement a mirroring solution for HA of the UPA. A very small change, but today (well yesterday) is a very good day indeed.