Read-only scale-out in a database mirroring system

For information about using high availability and/or read-only scale-out for hosting web applications, see SQL Anywhere web services high availability and scale-out solutions.

In a database mirroring system, you can access the database running on the mirror server using a read-only connection. This functionality is useful if you want to offload reporting or other operations that require read-only access to this database. The only difference between a mirror server and a copy node is that a copy node cannot participate as a primary or mirror server in a database mirroring system. A copy node can act as an arbiter for a database that it copies.

You can use database mirroring with read-only scale-out to ensure the availability of the root node. When scale-out is used with database mirroring, the root node of the scale-out system consists logically of the primary, mirror, and arbiter servers, instead of a single database server.

A read-only scale-out system with a database mirroring system as the root node.

Once you start the database servers in the mirroring system, additional database servers can access the participating mirror servers to maintain read-only copies of the database. You can add as many branches of copy nodes to the mirror servers as necessary.

 Differences between copy nodes and primary and mirror servers
 See also