|Routing Rule||Read System||Read||Write System||Create Write||Error Profile|
|RoutingB||TD1, TD2||Preferred||TD1, TD2, TD3||None||DefaultProfile|
|RoutingC||TD1, TD2||Default||TD1, TD2, TD3||None||DefaultProfile|
|RoutingD||TD3, TD1||Preferred||TD3, TD1||Preferred||DefaultProfile|
|RoutingE||TD1, TD2, TD3||Default||TD1, TD2, TD3||Balanced||DefaultProfile|
RoutingA describes a Read-only rule with Preferred routing to a single system. A session is only created on system TD1. All Read requests are sent to system TD1, and Write requests are rejected. A TD1 system failure will return an error to the client. Any errors classified as RESUBMIT will be returned as errors to the client.
RoutingB describes a Read/Write rule with Read routing to Preferred systems TD1, TD2 using Write systems TD1, TD2, and TD3. Sessions are created on TD1, TD2, and TD3. All Read requests are routed to TD1, and only if needed to TD2. Write requests are sent to TD1, TD2, and TD3 depending on which system the data objects reside.
RoutingC describes a Read/Write rule with Default routing. Routing C is identical to Routing B except that it uses automated routing and distributes Reads to both TD1 and TD2 using the shortest queue algorithm to balance the workload.
RoutingD describes a Read/Write rule with Preferred Read routing to TD3, TD1 using Write systems TD3 and TD1. Sessions are created on TD1 and TD3. All Read requests are routed to TD3 and only if needed to TD1. Write requests are sent to both TD3 and TD1. Write requests that also affect data objects on TD2 are rejected. This rule uses Create Preferred routing which means that CREATE statements are executed preferably on TD3 and use TD1 only if TD3 is unavailable.
RoutingE describes a Read/Write rule with automatic Read routing to TD1, TD2, TD3 using Write systems TD1, TD2, TD3. Sessions are created on TD1, TD2, TD3. Read requests are balanced among the systems that resolve each request. Write requests are sent to all systems that contain the data object requested. This rule uses the CREATE ROUTING - BALANCED routing which means that the CREATE statement is executed on one system for each session created. The system used for the CREATE statement for the session is selected from TD1, TD2, TD3 at the start of the session and will not change unless failover occurs on the preferred system.
DefaultRouting describes a Read/Write rule that includes all systems that are managed by Unity at the time of logon. All systems receive both Read and Write requests. Sessions are created on all systems. Read requests are automatically routed using the shortest queue algorithm to load balance across all systems. Write requests are also sent to all systems. The DefaultRouting routing rule always exists and cannot be deleted.