High Performance MySQL, 3rd edition, is by far the best book out there on performance and other issues. I have a bookshelf of 20+ MySQL books, some of which deal with performance. None are as clear, insightful or full as this book.
You should also note the 3rd edition has just been published a few months ago, and it is very up-to-date with current MySQL development.
Among other issues, it speaks of:
- Schema design
- Performance tuning
- High availability
- MySQL on the cloud
And lots more. Is is very practical and is based on the experience of its authors as employees/founders of Percona, a MySQL consulting company, as consultants and developers of MySQL and popular MySQL tools.
The MySQL High Availability book suggested in another answer, is centralized around MySQL replication. It is a good book, but does not provide with a thorough review & comparison of available HA solutions. It is authored by developers of Replication within Oracle/MySQL and covers replication in great depth.
There's a High Availability MySQL Cookbook, which provides a good overview of available HA solutions (already out-of-date as of Galera's appearance, and the demise of other solutions). I think it shows the basics well, so you can get the general picture.