Glossary

RAC - Oracle RAC is a clustered database solution with a shared memory cache. Oracle RAC is a "shared-everything" cluster as opposed to a "shared-nothing" architecture. In a "shared-everything" cluster, all nodes of the cluster (database instances) write to the same shared disks. A cluster allows multiple servers to act as a single server. A "shared-everything" cluster also allows RAC to improve performance by allowing each database server in the cluster to share a common memory area called Cache Fusion. Cache Fusion reduces the need for distributed locks.

Relational Database - Also covers an RDBMS. A relational database is a database that organizes its data in groups of rows called tables. These table have keys that relate the data to other tables. Examples of relational databases are Oracle, Postgres and MySQL.

Replication - Copying data from one database to another.