[jpterry]

Firstly, I can attest that migrating the datastore of an application which has scaled to require a NoSQL solution is no trivial task.

Secondly, I believe the author of the original posting really meant that "premature optimization is the root of all evil." Like this post points out, NoSQL solutions vary wildly in their abilities and usefulness. A relational database is a good place to start on the path to an MVP. And if you need features that a NoSQL solution can provide, and you understand the problem you're trying to solve, then use a NoSQL solution.

[jzawodn]

I think that most people who argue that such a migration "isn't that bad" haven't actually done it. Or at least they haven't done it for anything sizable.

[j-kidd]

It matters little how bad the migration is, when you ain't gonna need it in 99.9% of cases. When you are big enough to need the migration, your company has enough resources to roll your own Hadoop distribution.