On Unix and Linux, the database system uses the special operating system user <sdb_user>. The system default for the name of <sdb_user> is sdb. <sdb_user> was introduced so that there is a unique owner of the database resources, and so that other operating system users cannot have direct, unprotected operating system access to database resources.
<sdb_user> is the owner of the following database resources:
Caution
<sdb_user> is not intended for an administrator to log on to the operating system as this operating system user. For administration tasks, use any other operating system user that is a member of the <sdba_group> operating system group.
For security reasons, <sdb_user> must not be an interactive user. You can only install the database software when the user account for <sdb_user> is locked. If necessary, remove the authorization for <sdb_user> to log on to the operating system interactively. For more information, see the documentation for your operating system.
<sdb_user> must belong to the following operating system groups:
<sdba_group> (primary group)
Support groups of all databases (if they exist)