In a database mirroring system, you can access the database running on the mirror server using a read-only connection. This functionality is useful 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.

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. Add as many branches of copy nodes to the mirror servers as necessary.

 Differences between copy nodes and primary and mirror servers

 See also