OBProxy provides stateless proxy services. An OBProxy supports up to 8192 client connections. You can modify this upper limit by setting the client_max_connections parameter. However, we recommend that you do not modify it unless necessary, because it may cause a memory shortage on the server of OBProxy.
The ultimate solution to handle the rapid increase in business in an OceanBase cluster is to scale out the OBProxy service. Load-balancing is an important technique used in scaling. You can deploy OceanBase Database on Alibaba Cloud (Apsara Stack) or in your on-premises environment. Each deployment mode supports different load-balancing options. OceanBase Database may use one of the three following load-balancing technologies:
Alibaba Cloud (Apsara Stack) SLB
F5
DNS
Alibaba Cloud (Apsara Stack) SLB
When OceanBase Database is deployed on Alibaba Cloud (Apsara Stack), the applications are deployed on the ECS instances in a VPC, but OBServers are deployed in a classic network. OBProxy is installed on some of the OBServers (also known as OBProxy servers). You can use OBProxy servers as the backend servers of a Server Load Balancer (SLB) instance. The SLB instance provides the virtual IP address (VIP) and port number of OceanBase Database for applications to access. The following figures describe this topology.
SLB provides layer-4 and layer-7 load-balancing. It performs health check on backend servers, automatically blocks abnormal ones, and unblocks them after they return to normal. SLB also supports access control based on a whitelist. Only IP addresses in the whitelist can access the SLB service.
F5
You can also deploy OceanBase Database independently on the supported servers in your on-premises environment. If you have an F5 load balancer, you can use it for OBProxy. The deployment architecture is similar to that of SLB. You only need to replace SLB with F5.
We recommend that you set F5 to the routing mode. For OceanBase Cloud Platform (OCP) and OceanBase Developer Center (ODC), set the Virtual Server to the Standard type. For OBProxy, set the Virtual Server to the Performance Layer 4 type.
DNS
When you deploy OceanBase Database in your on-premises environment but do not use an F5 load balancer, you can use DNS for load-balancing. However, this mode is not fault-tolerant and has some risks because it cannot detect server faults or automatically block a failed server. It does not support many load-balancing algorithms or the whitelist mechanism.