IBM eServer zSeries 900 Technical Guide

238 IBM eServer zSeries 900 Technical Guide

z/VM and VM/ESA migration path

Figure 7-3 shows two typical migration paths to the z900 - z/VM - 64-bit real (z/architecture

mode).

Figure 7-3 One-step-at-a-time migration path examples for VM

The difference between the two paths is whether to start the H/W upgrade or S/W upgrade

first.

򐂰 Path #1: a -> b -> c, is the preferred path if the current VM operating system level supports

the z900 server.

򐂰 Path #2: d-> e -> c, is the preferred path if the current VM level operating system level

does not support the z900 server.

You can assign both Central Storage (CS) and Expanded Storage (ES) on z/VM 64-bit

addressing mode so that guest operating systems can use ES.

7.8.2 Considerations after concurrent upgrades

Using CUoD, CIU or CBU, you can concurrently upgrade your z900 from one model to

another, either temporarily or permanently. We need to consider the effect on the software

running on a z900 when performing a CUoD, CIU, or CBU upgrade on a z900 processor.

Enabling and using the additional processor capacity should be transparent to all

applications. There is, however, a small class of applications that obtains the processor

model-related information, for example, software monitors and those applications that use the

processor model information as a means of verifying the processor's capacity.

There are two instructions used to obtain the processor model information:

򐂰 STIDP: Store CPU ID instruction

STIDP instruction provides a 1-byte hexadecimal version code, which is

x'00' on any

z900 server. The STIDP instruction also provides information on the processor type

(2064), serial number, and model.

z/VM

z/VM

(32-bit)

Software level upgrade

Hardware upgrade to z900

Architecture level u pg rade to 64-bit

d

a

Current

VM

Current

Processor

e

Current

Processor

z/VM

z/VM

64-bit

64-bit

z/VM

z/VM

(32-bit)

b c

Current

VM

z900

z900

z900

z900

z900

z900