[grifferz]

As the article tries to state, the problem isn't that bad blocks can happen. The problems with md's bad blocks log are:

- Most of the time the entries don't correspond to actual bad blocks.

- It's buggy because it copies BBL between devices leading to another instance of "says the blocks are bad but they actually aren't"

- Once you've worked out that the entries are bogus it is still very hard to remove the entries or the BBL as a whole

- It's overly quiet in what it does. I monitor my syslogs but many people don't. There are many documented instances of people carrying entries in a BBL for years without knowing.

- Once MD thinks there is a bad block it renders that block on that device useless for recovery purposes. So in a two device array you just lost redundancy.

So this article has very little to do with the concept of bad blocks; it's about how md's BBL feature can be dangerous and why I don't want it enabled until it's fixed.