Every DB2® instance has one instance-owning user that is assigned when the instance is created. All instance functions are performed under the user name that was that assigned when the instance was created. One user name can be used for only one instance.
Each instance owner must have a unique home directory. All of the files necessary to run the instance are created in the home directory of the instance-owning user. If the instance owner's user name is removed from the system, you can lose files associated with the instance and lose access to data stored in this instance. It is recommended that you dedicate a user ID exclusively to own DB2 instances.
The primary group of the instance-owning user automatically becomes the system administration group for the instance and gains SYSADM authority over the instance. SYSADM is the highest level of administrative authority. Users with SYSADM authority can run utilities, issue database and database manager commands, and access the data in any table in any database within the database manager instance.
Each member of the primary group of the instance owner also gains this level of authority. To control access, you can assign the instance-owning user to a primary group that is reserved for instance administration. Ensure that you assign a primary group to the instance-owning user; otherwise, the system-default primary group is used. If you have a group that you want to make the system administration group for the instance, you can assign this group as the primary group when you create the instance-owning user. If you want to create a new group, enter a new name.
To separate SYSADM authority between instances, ensure that each instance-owning user uses a different primary group. If you choose to have a common SYSADM authority over multiple instances, you can use the same primary group for all the instance owners.
In a Network Information Services (NIS) environment, users and groups are remotely managed from an NIS server. Users and groups that you want to use with your DB2 product must exist on the NIS server prior to installation. The DB2 Setup wizard cannot create users or groups in an NIS environment.
To create a new user ID to be the instance-owning user ID, click New user and provide the required information for the instance-owning user.
The User name you specify must be a valid DB2 user ID. Valid DB2 user IDs:
A UID is a number that uniquely identifies a user. If you want a specific UID to be used, type it in the UID field. Otherwise, select Use default UID to use a system-generated UID.
The Group name you type can be an existing group you have defined, or a new group that will be created if it does not exist. The group must be the primary group of the user.
A GID is a number that uniquely identifies a group. If you are creating a new group and you want a specific GID to be used, type it in the GID field. Otherwise, select Use default GID to use a system-generated GID. If the group already exists, then the GID field will be filled and Use default GID will be disabled.
The Password you specify must contain 1 to 8 characters.
Confirm the password by typing it again in the Confirm password field.
The Home directory is used for storing all information that pertains to the database instance.
You cannot change the location of the directory once it is created.
In a partitioned database environment, the instance directory is shared among all database partitions that belong to the instance. Therefore, it must be created on an NFS mountable drive that all computers in the instance can access.
You can type a valid new directory or click [...] to select an existing directory, although permission problems could arise if an existing directory is used.
The DB2 Setup wizard will check the user ID, home directory and password for validity. The user ID and password are stored in the operating system security files.
The DB2 Setup wizard will verify that the user name follows the naming rules and that no instance currently exists in the user's home directory.
Click Existing user to use an existing user ID. You can type a valid User name or click [...] to select an existing user name.