Currently the switchdc cookbooks via spicerack ignore active/active dbs (parsercache, x2). It would be a good improvement if it verified that active/active dbs are read-write in both DCs. Or at the very least verify it's read-write in the new primary DC.
I don't really know how much DBAs have worked on the spicerack stuff so far if y'all want to do it, otherwise this is on my list of stuff to get to eventually, but I don't want to cookie lick.
No, I don't think this is a blocker (sidenote: I tried to add everything I actually thought was a blocker to the tracking task) because the status quo is that we've never automatically checked parsercache is read-write in both DCs and x2 still isn't in use yet. I added a note that parsercaches should be manually checked: https://wikitech.wikimedia.org/w/index.php?title=Switch_Datacenter&type=revision&diff=1922601&oldid=1921550