Based on best practices, I'm wondering if we should have at least one slave that's used solely as a backup server, without servicing any forward-facing requests from users.
For example, if we have a master server with a single slave, and that slave is used to back up data via mysqldump a few times a day, are there any compelling reasons not to use that same slave to calculate some quick-to-load (<10 seconds) analytics for a handful of customers in production?