Configuring a TCP/IP network (Linux)

The topics in this section detail how to configure a Transmission Control Protocol/Internet Protocol over Ethernet (TCP/IP) network.

No additional hardware, firmware, or software is required to install Db2® pureScale® Feature on a TCP/IP network. The only requirement is to have a network that is accessible by all the hosts. The hosts must be able to access each other, and all hosts must be on the same subnet. In addition, the /etc/hosts file entries on each of the hosts in the cluster must adhere to the following format: <IP_Address> <fully_qualified_name> <short_name>.

For example, in a 2 member/2 CF pureScale environment running on a TCP/IP network where there is both a public network and a private cluster interconnect network, the /etc/hosts configuration file might resemble the following:

9.26.51.101 member1.example.com member1
9.26.51.102 member2.example.com member2
9.26.51.103 cfhost1.example.com cfhost1
9.26.51.104 cfhost2.example.com cfhost2
10.1.2.1 member1-priv.example.com member1-priv
10.1.2.2 member2-priv.example.com member2-priv
10.1.2.3 cfhost1-priv.example.com cfhost1-priv
10.1.2.4 cfhost2-priv.example.com cfhost2-priv

It is a best practice that the TCP/IP network is 10 Gb or higher. However, if the workload has only modest network usage requirements, to avoid the Db2 product from blocking a network slower than 10 Gb, enable the registry variable DB2_SD_ALLOW_SLOW_NETWORK.

TCP/IP networking is recommended for light-to-moderate database workloads, with less than roughly 20% of SQL statements making changes to the database (e.g. Update / Insert / Delete). TCP/IP networking can use a significant amount of CPU on each active system. All critical clusters should have continuous monitoring for both database and system utilization, to provide the insights into any bottlenecks limiting the performance of the solution.

For workloads with a higher number of changes to the database, RDMA networking (e.g. with RoCE adapters) provides a better performing solution than TCP/IP due to the lower network latency, on-adapter network processing which reduces CPU utilization on each host and specific database engine enhancements which exploit RDMA features.

You set up your TCP/IP network as you normally would, set up all hosts on the same subnet, and test the host name resolution and connectivity.

If multiple adapter ports are assigned to each member or CF, ensure those network interfaces are bonded so that only the bonded interface is specified as the NETNAME column in the db2instance -list output. All NETNAME listed in the output should be in the same IP subnet.