DB2 Version 9.7 for Linux, UNIX, and Windows

Disk and memory requirements

Ensure that an appropriate amount of disk space is available for your DB2® environment, and allocate memory accordingly.
Important: For the most up-to-date installation requirements for DB2 database products, you must start using the System requirements for IBM® DB2 for Linux, UNIX, and Windows and System requirements for IBM DB2 Connect™ technotes. These technotes use 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 DB2 database products. This DB2 Information Centre topic might be removed in a future release or fix pack.

Disk requirements

The disk space required for your product depends on the type of installation you choose and the type of file system you have. The DB2 Setup wizard provides dynamic size estimates based on the components selected during a typical, compact, or custom installation.

Remember to include disk space for required databases, software, and communication products.

On Linux and UNIX operating systems, 2 GB of free space in the /tmp directory is recommended.

Note: On Linux and UNIX operating systems, you must install your DB2 product in an empty directory. If the directory that you have specified as the install path contains subdirectories or files, your DB2 installation might fail.

Memory requirements

Memory requirements are affected by the size and complexity of your database system, the extent of database activity, and the number of clients accessing your system. At a minimum, a DB2 database system requires 256 MB of RAM1. For a system running just a DB2 product and the DB2 GUI tools, a minimum of 512 MB of RAM is required. However, 1 GB of RAM is recommended for improved performance. These requirements do not include any additional memory requirements for other software that is running on your system. For IBM data server client support, these memory requirements are for a base of five concurrent client connections. For every additional five client connections, an additional 16 MB of RAM is required.

For DB2 server products, the self-tuning memory manager (STMM) simplifies the task of memory configuration by automatically setting values for several memory configuration parameters. When enabled, the memory tuner dynamically distributes available memory resources among several memory consumers including sort, the package cache, the lock list, and buffer pools.

Paging space requirements

DB2 requires paging, also called swap to be enabled. This configuration is required to support various functions in DB2 which monitor or depend on knowledge of swap/paging space utilization. The actual amount of swap/paging space required varies across systems and is not solely based on memory utilization by application software. It is only strictly required by DB2 on the Solaris and HP platforms due to their use of early paging space allocation.

A reasonable minimum swap/paging space configuration for most systems is 25-50% of RAM. Solaris and HP systems with many small databases or multiple databases tuned by STMM might require a paging space configuration of 1 x RAM or higher. These higher requirements are due to virtual memory pre-allocated per database / instance, and retained virtual memory in the case of STMM tuning multiple databases. Additional swap/paging space might be wanted to provision for unanticipated memory overcommitment on a system.

1 DB2 products that run on HP-UX Version 11i for Itanium-based systems require a minimum of 512 MB of RAM.