In the co-located topology, the Application Server instance and the HADB nodes are on the same machine (hence the name co-located). This topology requires fewer machines than the separate tier topology. The co-located topology uses CPUs more efficiently—an Application Server instance and an HADB node share one machine and the processing is distributed evenly among them.
This topology requires a minimum of two machines. To improve throughput, add more machines in pairs.
The following figure illustrates an example configuration of the co-located topology.
Machine SYS0 hosts Application Server instance A, machine SYS1 hosts Application Server instance B, machine SYS2 hosts Application Server instance C, and machine SYS3 hosts Application Server instance D.
These four instances form a cluster that persists information to the two DRUs:
DRU0 comprises two machines, SYS0 and SYS2. HADB node active 0 is on the machine SYS0. HADB node spare 2 is on the machine SYS2.
DRU1 comprises two machines, SYS1 and SYS3. HADB node active 1 is on the machine SYS1. HADB node spare 3 is on the machine SYS3.
For better scalability and throughput, increase the number of Application Server instances and HADB nodes by adding more machines. For example, you could add two machines, each with one Application Server instance and one HADB node. Make sure to add the HADB nodes in pairs, assigning one node for each DRU. Variation of Co-located Topology illustrates this configuration.
In this variation, the machines SYS4 and SYS5 have been added to the co-located topology described in Example Configuration.
Application Server instances are hosted as follows:
Machine SYS0 hosts instance A
Machine SYS1 hosts instance B
Machine SYS2 hosts instance C
Machine SYS3 hosts instance D
Machine SYS4 hosts instance E
Machine SYS5 hosts instance F
These instances form a cluster that persists information to the two DRUs:
DRU0 comprises machines SYS0, SYS2, and SYS4. HADB node active 0 is on the machine SYS0. HADB node active 2 is on the machine SYS2. HADB node spare 4 is on the machine SYS4.
DRU1 comprises the machines SYS1, SYS3, and SYS5. HADB node active 1 is on the machine SYS1. HADB node active 3 is on the machine SYS3. HADB node spare 5 is on the machine SYS5.