Limitations of non-root installations

Non-root installations have limitations, beyond the differences with root installations. Limitations are covered here to help you decide whether you want to use a non-root installation.

Important: Net Search Extender (NSE) is no longer supported in Db2®. Use the Db2 Text Search feature.
Product limitations
Some Db2 database products are not supported in non-root installations:
  • Db2 Net Search Extender
  • Locally installed Db2 Information Center
    Note: The locally installed Db2 Information Center is not supported in non-root installations because it requires root user authority to start the daemon. However, a non-root-installation Db2 instance can be configured to use a locally installed Db2 Information Center if it is installed on the same computer.
Features and tools limitations
The following features and tools are not available in non-root installations:
  • The Db2 Administration Server (DAS) and its associated commands, dascrt, dasdrop, daslist, dasmigr, and dasupdt
  • The ability for the db2governor to increase priority is not supported
  • Automatic starting of non-root Db2 instances at system restart is not supported
Health monitor limitations
The following health monitor features are not supported in non-root installations:
  • Running script or task actions on alert occurrences
  • Sending alert notifications
Partitioned database limitation
Only single-partition databases are supported in non-root installations. You cannot add more database partitions.
Listing Db2 database products
The output that is produced by the db2ls command, when run as a non-root user, is different than the output produced when run as a root user. For more information, see the db2ls command topic.
Db2 copies
Each non-root user can have only one copy of a Db2 database product installed.
Db2 instance limitation
In non-root installations, one Db2 instance is created during installation. More instances cannot be created.
Limitation for db2start or db2stop
Only the instance owning ID is allowed to db2start or db2stop the instance on a non-root installation.
Db2 instance actions can be completed only by the instance owner
Root installations and non-root installations can coexist on the same computer in different installation paths. However, a non-root instance can be updated, or dropped (by using the db2_deinstall command), only by the non-root user who owns the non-root instance.

A Db2 instance that is created by a user with root user authority can be updated or dropped only by a user with root user authority.

Upgrading limitation
Root instances cannot be upgraded to a non-root instance.
Manual kernel parameter updates
Automatic Linux kernel parameter modification is not supported for non-root installations. Kernel parameters in non-root installations must be updated manually as described in the "Modifying Kernel Parameters (Linux)" topic.
Post-installation actions can be completed only by the Db2 instance owner
Root installations and non-root installations can coexist on the same computer. However, only the original non-root user who installed the Db2 database product can perform subsequent actions such as:
  • Applying fix packs
  • Adding features
  • Installing add-on products
Adjusting ulimit values
The ulimit command on UNIX and Linux® operating systems sets or reports user resource limits, such as data and stack limits. For root instances, the database server dynamically updates ulimit settings without changing the permanent settings. However, for non-root instances, the ulimit settings can be checked only during installation. A warning message is displayed if the settings are inadequate. Root user authority is required to change the ulimit settings.

Limitations that can be overcome by running db2rfe

Further limitations on non-root installations can be overcome by running the db2rfe command. The following features and abilities are initially unavailable in non-root installations:
  • Operating system-based authentication
  • High Availability (HA) feature
  • The ability to reserve service names in the /etc/services file
  • The ability to increase user data limits (ulimits). This ability applies only to AIX®. On other operating systems, user data limits must be increased manually.

Run the Enable root features for non-root installation command (db2rfe) to enable these features and abilities. Running the db2rfe command is optional, and must be run by a user with root user authority.

Authentication type in non-root installations

Operating system-based authentication is the default authentication type for Db2 database products. Non-root installations do not support operating system-based authentication. If you choose not to run the db2rfe command after you install your Db2 database product as a non-root user, then you must manually set the authentication type. You can do so by updating the following parameters in the database manager configuration file:
  • clnt_pw_plugin (Client userid-password plug-in configuration parameter)
  • group_plugin (Group plug-in configuration parameter)
  • srvcon_pw_plugin (Userid-password plug-in for incoming connections at the server configuration parameter)