Currently Cloud Stack has only one active master DB setup. Going forward it should support multiple Master/Slave cluster setup to enable High Availability of the Database.
Scope
To Achieve Active/Active cluster set up (Multiple masters and slaves).
Options Available
MariaDB
Percona Xtra DB (uses Galera cluster)
MHA provided by SkySql
Mysql Active/Active setup with connector specific configuration to read from slaves in case of master goes down
Results
MariaDB
It does not support any DB HA out of the box, we can use Galera with it but the same can be used with Mysql directly
h3 Percona Xtra DB