Parallel Sysplex Cluster Technology

Sparing for Storage Protect Keys: The robust conﬁ guration of the Storage Protect Keys has been enhanced with chip sparing. Already a triple-array with parity protection and voting, the Key structure for z890 has added sparing, simi- lar to Main Memory chip sparing, to further enhance the availability of this critical function.

Failure Containment for the Memory Bus Adapter (MBA): Memory Bus Adapters are designed to provide the critical link between the z890 Processor Units and the I/O subsys- tem. The Model A04 has two MBAs. In the unlikely event of a catastrophic failure of an MBA chip, the z890 is designed to isolate the failure of that chip such that the remaining MBA chips continue to operate. This helps minimize the impact of a failure and allows for scheduling maintenance.

Enhanced Firmware Simulation: The z890 process for design, development, and test of Licensed Internal Code (LIC) has been signiﬁ cantly enhanced with the use of simulation to improve quality and early availability. Virtu- ally every action/reaction of the code can be tested with the simulated hardware/code of the rest of the server. The result is to discover and correct design errors much earlier in the process.

These new features, together with legacy features such as high levels of recovery, concurrent processor upgrade, concurrent memory upgrade, concurrent I/O upgrade, and concurrent maintenance for hardware and LIC give the z890 a very impressive RAS structure.

Parallel Sysplex clustering was designed to bring the power of parallel processing to business-critical zSeries and S/390 applications. A Parallel Sysplex cluster consists of up to 32 z/OS and/or OS/390 images coupled to one or more Coupling Facilities (CFs or ICFs) using high-speed specialized links for communication. The Coupling Facili- ties, at the heart of the Parallel Sysplex cluster, enable high speed, read/write data sharing and resource sharing among all the z/OS and OS/390 images in a cluster. All images are also connected to a Sysplex Timer® to address time synchronization.

Parallel Sysplex Resource Sharing enables multiple system resources to be managed as a single logical resource shared among all of the images. Some examples of resource sharing include JES2 Checkpoint, GRS “star,” and Enhanced Catalog Sharing; all of which provide sim- pliﬁ ed systems management, increased performance and/or scalability. For more detail, please see S/390 Value of Resource Sharing White Paper – GF22-5115 on the Parallel Sysplex home page at ibm.com/servers/eserver/ zseries/pso.