Jeffrey P. Kubala

Logical partition mode physical resource management on the IBM eServer z990

The IBM eServerTM z990 provides tremendously increased processor, I/O, and memory capacity exceeding the capability of even the premier IBM operating systems. The modular or book-form system topology of the z990 enables a highly flexible and more cost-effective concurrent upgrade infrastructure, as well as improved hardware failure survivability and serviceability. The multibook form of the z990 has two significant memory access performance issues which are addressed here: First, there is increased cache coherency overhead when the same memory is accessed by central processing units (CPUs) from multiple books; second, access from CPUs to memory on books other than the book on which a CPU is resident is not as efficient as access from the same book. Awareness of this multifold increase in capacity and complexity is effectively managed by the IBM zSeries® logical partition (LPAR) hypervisor, obviating the need for operating system involvement. This paper describes changes made to the zSeries LPAR hypervisor to manage CPU and memory resources on the z990 machine topology.

Intelligent resource director

Intelligent Resource Director (IRD), a feature of the IBM eServer zSeries™ processors and the z/OS™ operating system, manages multiple heterogeneous workloads with various business priorities toward achieving their goals. It establishes a more synergistic relationship with the Workload Manager (WLM) component of z/OS and the zSeries hardware, and augments the adjustments that WLM makes to local sysplex members by managing the set of logical partitions on a particular central processing complex (CPC) that are part of the same sysplex, known as a logically partitioned (LPAR) cluster. This paper describes the three primary areas that IRD manages: LPAR CPU management, channel subsystem priority queueing (CSSPQ), and dynamic channel path management (DCM).

IBM system z10 design for RAS

The IBM System z10™ server reliability, availability, and serviceability (RAS) design continues to reduce the sources of server outages through innovative RAS architecture and techniques. The z10™ server introduced functional improvements that challenged the RAS design. Increases were made in the performance of each processor, the total number of processors, the total size of the memory, the amount of cache, the bandwidth of the I/O, the thermal density, and the exposure to soft errors. These changes demanded stronger RAS functions to prevent unscheduled outages. Significant improvements were made to the IBM e-business on demand® functions (concurrent, customer-requested upgrades) that enable customers to better manage capacity without having to take planned outages. The hypervisor simplified configuration changes, such as adding cryptography or channel subsystems to logical partitions, by eliminating the need for preplanning. Single-core checkstopping and single transparent CPU (central processing unit) sparing were added. The RAS functions reduced the number of scheduled outages. Product improvements were complemented by improvements in RAS modeling. This paper describes these RAS improvements and how they provide value to the customer.

SCSI initial program loading for zSeries

This paper describes a new kind of initial program loading (IPL) for IBM zSeries® servers. The new IPL protocol expands the set of input/output devices that can be used during IPL to include Small Computer System Interface (SCSI) Fibre Channel protocol (FCP) disk devices (SCSI disks). We begin by describing several new challenges resulting from the use of SCSI disks during IPL, followed by a brief overview of new concepts we have applied to the IPL process to overcome these challenges. We continue with a step-by-step description of the processes executed during SCSI IPL, the tools used, the disk format, the parameters required, and related topics. Since SCSI IPL is supported for virtual machines instantiated by the z/VM® operating system, some unique features of this capability are described. Finally, we describe a variation of SCSI IPL that enables the contents of memory to be dumped onto a SCSI disk.

zAAPs and zIIPs: increasing the strategic value of System z

With the addition of IBM System zTM application assist processors (zAAPs) and integrated information processors (zIIPs) to the portfolio of special-purpose IBM System z processors, the reinvention of the IBM mainframe continues. Jointly, zAAPs and zIIPs provide significant IBM System z9TM integrated and cost-effective processing cycles for todays strategic JavaTM and DB2® for z/OS® programming platforms which are increasingly fundamental to enterprise-class business environments. Overviews of zAAPs and zIIPs are presented that describe their functionality, design, and use by the z/OS operating system to achieve the execution of both Java and z/OS DB2 programming, functions.