Administration tools metadata

The Administration Tools configuration data (metadata) contains information that databases need to start, such as the hostname/IP address of each participating host in the database cluster.

To facilitate hostname resolution within the Administration Tools, all hostnames you provide through the Administration Tools use IP addresses at the command line and inside the installation utility as follows:

• During installation

  The installation script immediately converts all hostnames you provide through command line options --hosts, -add-hosts or --remove-hosts to their IP address equivalent.

  • If you provide a hostname during installation that resolves to multiple IP addresses (such as in multi-homed systems), the installer prompts you to choose one IP address.

  • The database retains the name you give for messages and prompts only; internally it stores these hostnames as IP addresses.

• Within the Administration Tools

  All hosts are in IP form to allow for direct comparisons (for example db = database = database.example.com).

• At the command line

  The database converts any hostname value to an IP address that it uses to look up the host in the configuration metadata. If a host has multiple IP addresses that are resolved, the database tests each IP address to see if it resides in the metadata, choosing the first match. No match indicates that the host is not part of the database cluster.

Metadata is more portable because the database does not require the names of the hosts in the cluster to be exactly the same when you install or upgrade your database.