We've used master/master shards in the past and they've been very difficult to manage. I'm not fully aware of Gizzard's capabilities so I guess the answer is no

We've used master/master shards in the past and they've been very difficult to manage. I'm not fully aware of Gizzard's capabilities so I guess the answer is no, because we weren't aware of it. We also needed something that would speed up writes much more than just 2x (and the way ndbcluster does writes was the key).