Originally Posted by Fellow
Steve has given you the best link to refer to. I can tell you that it is important to keep other back up copies. I had a friend who recently lost around 3 months of posts because of a corruption. I would not risk having just one copy if the blog is of any importance to you.
I always keep a copy of my articles locally, as well as the data that goes with them, tags, categories, excerpts... I know that keeping database backups is better, but nevertheless I do this as well.