DB2 10.5 for Linux, UNIX, and Windows

Additional installation considerations (Linux)

Before you install data server products on Linux operating systems, ensure that the system you choose meets the necessary operating system, hardware, software, and communications requirements. The db2prereqcheck command checks whether your system meets the prerequisites for the installation.

For the most up-to-date installation requirements for data server products, see System requirements for IBM® DB2® for Linux, UNIX, and Windows. This techdoc uses IBM Software Product Compatibility Reports (SPCR). With the SPCR tool, you can locate and find complete lists of supported operating systems, system requirements, prerequisites, and optional supported software for these database products.

In addition to system requirements, installing a data server product on supported Linux operating systems has the following additional considerations:

If you are planning to install the IBM DB2 pureScale® Feature, different installation prerequisites are required. See the Installing the DB2 pureScale Feature topic.
For the most up-to-date requirements for DB2 database products, see http://www.ibm.com/support/docview.wss?uid=swg27038033.

Multithreaded architecture limitations

If you are installing a DB2 32-bit database product on a Linux operating system, consider upgrading to a 64-bit operating system and installing the DB2 64-bit database product instead. The multithreaded architecture generally simplifies memory configuration. However, this could affect the memory configuration of 32-bit DB2 database servers. For example:

Private memory for agent threads is allocated within a single process. The aggregate of all private memory allocations for database agents might not fit in a single process memory space.
Support for multiple databases is limited because all database shared memory segments for all databases are allocated in a single process. You might need to reduce the memory usage for some databases in order to activate all databases successfully at the same time. However, the database manager performance might be impacted. Another alternative is to create multiple instances and catalog the databases across the instances when you have sufficient system resources to support this configuration.

Distribution Requirements

You should update your kernel configuration parameters before installing a DB2 database product. The default values for particular kernel parameters might not be sufficient when running a DB2 database system.

You might also have other products or applications that require Linux system resources. You should modify the kernel configuration parameters based on the needs of your Linux system working environment.

The kernel configuration parameters are set in /etc/sysctl.conf.

Refer to your operating system manual for information about setting and activating these parameters using the sysctl command.

Package requirements

Table 1 lists the package requirements for SLES and RHEL distributions:

libpam.so.0 (32-bit) is required for DB2 database servers to run 32-bit non-SQL routines and JDBC type 2 driver applications in 32-bit JDK.
libpam.so.0 is required by IBM data server clients for DB2 user authentication.
libaio.so.1 is required for DB2 database servers using asynchronous I/O.
libstdc++.so.5 is required for Linux 390, installed under /usr/lib and /usr/lib64.
libstdc++.so.6.0.8 is required for DB2 database servers and clients.
libstdc++33 and libstdc++43 are required for SLES 11.
The ksh93 Korn shell is required for all DB2 database systems.

Table 1. Package requirements for SLES and RHEL
Package name	Description
libaio	Contains the asynchronous library required for data servers.
compat-libstdc++	Contains libstdc++.so.6 (not required for Linux on POWER® or SLES 11) Contains libstdc++.so.5 (required for Linux 390).
vacpp.rte	Contains 32 and 64 bit versions of libibmc++.so.1 (required for Linux on POWER big endian)
libxlc	Contains libibmc++.so.1 (64 bit only) (required for Linux on POWER little endian)
ksh93	Korn Shell

Table 2 and Table 3 list the package requirements for SUSE Linux and Red Hat distributions for DB2 partitioned database servers.

The ksh93 Korn shell is required for all DB2 database systems.
A remote shell utility is required for partitioned database systems. DB2 database systems support the following remote shell utilities:
- rsh
- ssh
By default, DB2 database systems use rsh when executing commands on remote DB2 nodes, for example, when starting a remote DB2 database partition. To use the DB2 database system default, the rsh-server package must be installed (see following table). More information about rsh and ssh is available in the DB2 Information Center.
If you choose to use the rsh remote shell utility, inetd (or xinetd) must be installed and running as well. If you choose to use the ssh remote shell utility, you need to set the DB2RSHCMD communication variable immediately after the DB2 installation is complete. If this registry variable is not set, rsh is used.
The nfs-utils Network File System support package is required for partitioned database systems.

All required packages should be installed and configured before continuing with the DB2 database system setup. For general Linux information, see your Linux distribution documentation.

Table 2. Package requirements for SUSE Linux. Package requirements for SUSE Linux
Package name	Description
pdksh	Korn Shell.
openssh	This package contains a set of server programs which allow users to run commands on (and from) remote computers via a secure shell. This package is not required if you use the default configuration of DB2 database systems with rsh.
rsh-server	This package contains a set of server programs which allow users to run commands on remote computers, login in to other computers, and copy files between computers (rsh, rexec, rlogin, and rcp). This package is not required if you configure data servers to use ssh.
nfs-utils	Network File System support package. It allows access to local files from remote computers.

Table 3. Package requirements for Red Hat. Package requirements for Red Hat
Directory	Package name	Description
/System Environment/Shell	pdksh	Korn Shell.
/Applications/Internet	openssh	This package contains a set of client programs which allow users to run commands on a remote computer via a Secure Shell. This package is not required if you use the default configuration of DB2 database systems with rsh.
/System Environment/Daemons	openssh-server\	This package contains a set of server programs which allow users to run commands from a remote computer via a Secure Shell. This package is not required if you use the default configuration of DB2 database systems with rsh.
/System Environment/Daemons	rsh-server	This package contains a set of programs which allow users to run commands on a remote computer. Required for partitioned database environments. This package is not required if you configure DB2 database systems to use ssh.
/System Environment/Daemons	nfs-utils	Network File System support package. It allows access to local files from remote computers.

Software considerations

(Client and Server) To use Kerberos authentication, install the Linux krb5 Kerberos support via the operating system Kerberos packages.
An X Window System software capable of rendering a graphical user interface is required if:
- You want to use the DB2 Setup wizard to install a DB2 database product on Linux or UNIX operating systems, or
- You want to use graphical tools on Linux for x86 and Linux on AMD 64/EM64T.
Micro Focus does not offer support for any of its COBOL compiler products on SLES 11.
If you plan on using transparent Lightweight Directory Access Protocol (LDAP) on RHEL 5, you must install nss_ldap-253-35.el5 or later.

Security-enhanced Linux considerations

On RHEL systems, if Security-enhanced Linux (SELinux) is enabled and in enforcing mode, the installer might fail due to SELinux restrictions.

To determine if SELinux is installed and in enforcing mode, you can do one of the following:

check the /etc/sysconfig/selinux file
run the sestatus command
check the /var/log/messages file for SELinux notices.

To disable SELinux, you can do one of the following:

set it in permissive mode and run the setenforce 0 command as a superuser
modify /etc/sysconfig/selinux and reboot the machine.

If your DB2 database product installs successfully on an RHEL system, DB2 processes will run in the unconfined domain. To assign DB2 processes to their own domains, modify the policy. A sample SELinux policy is provided in the sqllib/samples directory.