IBM z13s, Technical Manual

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Chapter 8. System upgrades
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In addition, two CP CBU features can be used to change the capacity level of permanent
CPs, and the third CP CBU feature can be used to add a CP, which enables the activation of
D03, E03, and F03 through Z03. In this example, you are offered 49 possible configurations at
activation time. While CBU is active, you can change the target configuration at any time.
8.7.3 Automatic CBU for Geographically Dispersed Parallel Sysplex
The intent of the IBM Geographically Dispersed Parallel Sysplex (GDPS) CBU is to enable
automatic management of the PUs provided by the CBU feature during a server or site failure.
Upon detection of a site failure or planned disaster test, GDPS concurrently adds CPs to the
servers in the takeover site to restore processing power for mission-critical production
workloads. GDPS automation does the following tasks:
򐂰 Performs the analysis that is required to determine the scope of the failure. This function
minimizes operator intervention and the potential for errors.
򐂰 Automates the authentication and activation of the reserved CPs.
򐂰 Automatically restarts the critical applications after reserved CP activation.
򐂰
Reduces the outage time to restart critical workloads from several hours to minutes.
The GDPS service is for z/OS only, or for z/OS in combination with Linux on z Systems.
8.8 Nondisruptive upgrades
Continuous availability is an increasingly important requirement for most customers, and even
planned outages are no longer acceptable. Although Parallel Sysplex clustering technology is
the best continuous availability solution for z/OS environments, nondisruptive upgrades within
a single server can avoid system outages, and are suitable to additional OS environments.
z13s servers support
concurrent
upgrades, meaning that dynamically adding more capacity
to the CPC is possible. If OS images running on the upgraded CPC do not require disruptive
tasks to use the new capacity, the upgrade is also
nondisruptive
. Therefore, POR, LPAR
deactivation, and IPL do not have to take place.
If the concurrent upgrade is intended to satisfy an
image upgrade
to an LPAR, the OS running
in this partition must also have the capability to concurrently configure more capacity online.
IBM z/OS OSs have this capability. IBM z/VM can concurrently configure new processors and
I/O devices online, and memory can be dynamically added to z/VM partitions.
If the concurrent upgrade is intended to satisfy the need for more OS images, more LPARs
can be created
concurrently
on the z13s CPC, including all resources needed by such
LPARs. These additional LPARs can be activated concurrently.
Linux OSs in general do
not
have the capability to add more resources concurrently. However,
Linux, and other types of virtual machines running under z/VM, can benefit from the z/VM
capability to non-disruptively configure more resources online (processors and I/O).
With z/VM, Linux guests can manipulate their logical processors by using the Linux CPU
hotplug daemon. The daemon can start and stop logical processors based on the Linux
load
average
value. The daemon is available in Linux SLES 10 SP2 and up, and in Red Hat
Enterprise Linux (RHEL) V5R4 and up.