> So now I'm confused ... Cassandra doc says that I have to run it by myself, > Cassandra book says I don't have to. > Did I misunderstand something?
The book is wrong, at least by current versions of Cassandra (I'm basing that on the quote you pasted, I don't know the context). nodetool repair must be scheduled by the operator to run regularly. The name "repair" is a bit unfortunate; it is not meant to imply that it only needs to run when something is "wrong". -- / Peter Schuller