Percona MySQL Consulting vs. Percona MySQL Support
Percona MySQL Consulting is billed on an hourly rate, covers all normal technologies in the LAMP stack, provides wide ranging strategic advice, and will directly implement any needed work for you.
Percona MySQL Support is paid via a fixed cost annual contract, covers only the MySQL database -- including Oracle MySQL, Percona Server, Drizzle, and MariaDB -- and their utilities, advises on how to troubleshoot specific MySQL problems but not on broad design analysis of your system, coaches you on how to implement changes, and provides fixes for source code bugs.
If you are not already a Percona customer, you can purchase emergency Percona MySQL Consulting immediately and receive quick help for an unexpected emergency. Annual Percona MySQL Support contracts require pre-purchase and hence are not an option in emergency cases.