oracle11g RAC for Solaris No DHCP, DNS uses scan for connection level load balancing

10g and previous versions to achieve load balancing, in addition to the purchase of specialized equipment, usually through the client configuration method to achieve.

With the Load_balance, AddressList properties of Oracle driver, the client Load Balancing is achieved by writing the IP of all the nodes into the configuration file, which is a problem that once the server side has changed , such as adding or removing cluster nodes, and when the node is changing, the client of all applications needs to modify the configuration.

11G started with the introduction of scan (single Client Access Name) and GNS (Grid naming Service) for server-side load Balancing :

SCAN--single Client Access name:

Client and RAC before the establishment of a layer, the purpose is to the RAC IP information to the customer shield off, so that users more convenient and transparent, do not have to go to the pipe to connect which instance, the new addition node or delete node, the client does not need to do any configuration, the purpose is to: extensibility.

Gns--grid naming Service

With scan, you can not configure the IP address of the RAC and use the DHCP service to assign IP

Oracle official recommended Gns+scan method, you can hide the cluster nodes of the IP, the client only through a specific name to access the cluster, do not need to ignore the cluster node increase or decrease or IP changes, but still need to rely on DNS and DHCP services, the client also needs to set a specific DNS address, Multiple points of failure in the actual production environment is not useful.

Thus there is a most streamlined way to achieve server-side load balancing in the least-effort situation.

3 node cluster, installation essentials are as follows:

1. Only 1 Scanip can be set without enabling GNS, which is written in the Hosts file, in this case 192.168.132.110

2. Do not tick gns during installation of the grid

3. After installing the database, you need to modify the host of the node Local_listener attribute to the virtual IP of the node, otherwise the client cannot connect the database with Scanip;

4. Client configuration file (only need to scanip, do not need to know the virtual IP of each node)

Load balancing test: Make a small program, connect to the database with 100 processes, and output the number of hits per node.

Test Result: Each node is maintained at about 33%.

oracle11g RAC for Solaris No DHCP, DNS uses scan for connection level load balancing