IBM Parallel Sysplex: Difference between revisions

Revision as of 09:26, 11 March 2007

Revision as of 05:14, 8 August 2007

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* Software ([[operating system]] services and, usually, [[middleware]] such as [[IBM DB2|DB2]]).

The Coupling Facility may be either a dedicated external system (a small mainframe specially configured with only coupling facility processors) or integral processors on the mainframes themselves configured as ICFs (Internal Coupling Facilities). Both are popular — there are minor technical advantages and disadvantages between external CF and ICF installations. For achieving highest availability without unnecessary spending, IBM generally recommends combining a single external CF with an ICF.

A Parallel Sysplex has at least two CFs or ICFs for redundancy (or at least one of each). Every mainframe participating in a Parallel Sysplex does not need an ICF or its own external CF — mainframes merely attach, via cables, to the external CFs or ICFs.

Server Time Protocol (STP) replaced the Sysplex Timers beginning in 2005 for newer mainframe models. While the Sysplex Timers are physically separate machines, STP is an integral feature within the mainframe itself. With STP and ICFs it is now possible (and common) to construct a complete Parallel Sysplex installation solely with two mainframes and cabling. Moreover, a single mainframe can contain the internal equivalent of a complete physical Parallel Sysplex, so there is no technical requirement to have ana actualmulti-frame Parallel Sysplex for application testing and development purposes.

==See also==