SQL Anywhere read-only scale-out

Note

Read-only scale-out requires a separate license. See Separately licensed components.

Read-only scale-out is a configuration that allows you to offload reporting or other operations that require read-only access to the database.

A scale-out tree consists of the root node and copy nodes. The root node of a scale-out system has the only copy of the database that is writable. The root node can be either a single database, or a database mirroring system. Below the root node, there can be one or many branches of copy nodes. A copy node is a database server that runs a copy of a database for read-only access, and a copy node can be the parent of other copy nodes.

Diagram of a read-only scale-out architecture when used with database mirroring.

If you are using the NodeType connection parameter to redirect connections that use Kerberos authentication or integrated logins, all the database servers in the scale-out tree must be configured as follows:

  • Integrated logins   All of the database servers in the scale-out tree must be a part of the same Windows user group or be configured to allow the same Windows users to access them.

  • Kerberos authentication   All of the database servers in the scale-out tree must have Kerberos authentication enabled. The Kerberos server principal for all the servers in the scale-out tree must have the same realm.

 How scale-out works
 Connecting to a database in a scale-out system

Tutorial: Creating and monitoring a read-only scale-out system
Read-only scale-out set-up
How child copy nodes are added
Handle the loss of a parent connection
Connect to copy nodes
Dropping servers from a read-only scale-out system
Read-only scale-out in a database mirroring system
SQL Anywhere web services high availability and scale-out solutions