A bcache update

There's also the facebook flashcache which does something similar. I've been running it experimentally as a writeback cache on a test server and so far it seems to do what it promises. It can be experimented with today, and contains only about 6400 lines of code by a quick count, and can be insmod'd into kernel rather than patched in.

Maybe it's somehow critically far worse, but then again, perhaps it's true that perfect is the enemy of good. We'll probably know when we can benchmark these technologies against each other.