Oracle Essentials: Oracle9i, Oracle8i and Oracle8, Second Edition

Massively Parallel Processing Systems

Clusters historically have been limited in the throughput they can deliver by the number of physical shared disk connections possible, since the disks have to be linked physically to each system. Recent advances in serial and fiber channel disk technology (discussed in Section 11.7) have raised disk performance and capacity. But this increased capability has also raised issues of management complexity, because each node introduces another discrete copy of the operating system. With Real Application Clusters, managing the multiple Oracle instances that make up the cluster is essentially the same as managing a single instance, but the multiple machines and the underlying cluster hardware still make for a greater management burden.

Massively Parallel Processing (MPP) systems appeared in the early 1990s to address these limitations. Unlike clusters, the disks in an MPP environment are not shared across multiple nodes, except for high-availability configurations, so the architecture is sometimes called a "shared nothing architecture” (shown in Figure 11-4). A special console provides additional operating system-management tools to make management of the many operating system copies appear to be more transparent.

Figure 11-4. Massively Parallel Processing (MPP) configuration ( four SMP nodes shown)

In a typical MPP configuration multiple nodes reside ...