IBM manual DS8000 and Lpar, Lpar and storage facility images

application on separate smaller partitions can provide better throughput than running a single large instance of the application.

Increased flexibility of resource allocation

A workload with resource requirements that change over time can be managed more easily within a partition that can be altered to meet the varying demands of the workload.

3.2 DS8000 and LPAR

In the first part of this chapter we discussed the LPAR features in general. In this section we provide information on how the LPAR functionality is implemented in the DS8000 series.

The DS8000 series is a server-based disk storage system. With the integration of the POWER5 eServer p5 570 into the DS8000 series, IBM offers the first implementation of the server LPAR functionality in a disk storage system.

The storage system LPAR functionality is currently supported in the DS8300 Model 9A2. It provides two virtual storage systems in one physical machine. Each storage system LPAR can run its own level of licensed internal code (LIC).

The resource allocation for processors, memory, and I/O slots in the two storage system LPARs on the DS8300 is currently divided into a fixed ratio of 50/50.

Note: The allocation for resources will be more flexible. According to the announcement letter IBM has issued a Statement of General Direction:

IBM intends to enhance the Virtualization Engine partitioning capabilities of selected models of the DS8000 series to provide greater flexibility in the allocation and management of resources between images.

Between the two storage facility images there exists a robust isolation via hardware; for example, separated RIO-G loops, and the POWER5 Hypervisor, which is described in more detail in section 3.3, “LPAR security through POWER™ Hypervisor (PHYP)” on page 54.

3.2.1 LPAR and storage facility images

Before we start to explain how the LPAR functionality is implemented in the DS8300, we want to clarify some terms and naming conventions. Figure 3-2 on page 49 illustrates these terms.

48DS8000 Series: Concepts and Architecture