Before you upgrade WordPress, you need to back it up so you
don’t lose your blog posts, pages and anything else that can be lost on your
blog. This has happened to me on more than one occasion and it’s really not
worth the agro of having to go back to your hosting provider to ask them to
restore your blog. In some cases, this may not be possible.
This is a collection of video tutorials showing methods & tips for successful backup of a WordPress blog: