Hostname resolution configuration (Linux)

Implementing a fast hostname resolution scheme is essential in building a well-performing Db2 pureScale cluster.

Many operations involve retrieving the hostname from the system. A miniscule delay in each hostname resolution can quickly compound and magnify to a serious performance problem when the frequency of these operations is high. While there are various ways hostname resolution can be configured, Db2 requires all hostname resolution to query the local configuration first before trying other methods that may require accessing a remote DNS server to minimize the delay spent on network.

On Linux, this can be achieved by ensuring the keyword files is defined as the first entry in the lines line in /etc/nsswitch.conf file. For example:

hosts: files dns nisplus