I think the back story here is that they are running MySQL as sharded key-value storage. And at 2300 instances, it makes sense that there would be a few of the

I think the back story here is that they are running MySQL as sharded key-value storage. And at 2300 instances, it makes sense that there would be a few of them dying at any given time. With this setup, using MySQL is pretty much arbitrary, any databases could fill in the role as well. E.g. It got me thinking that Redis+Sentinel could do the job too (if they don't need super durable transactions)