Considerations For Powerha In Zbx Environment - IBM z13s Technical Manual

9.7 Considerations for PowerHA in zBX environment

An application that runs on AIX can be provided with high availability by using the PowerHA
SystemMirror for AIX (formerly known as IBM HACMP™). PowerHA is easy to configure
because it is menu-driven, and provides high availability for applications that run on AIX.
PowerHA helps define and manage resources that are required by applications that run on
AIX. It provides service/application continuity through system resources and application
monitoring, and automated actions (start/manage/monitor/restart/move/stop).
Tip: Resource movement and application restart on the second server are known as
failover
Automating the failover process speeds up recovery and allows for unattended operations,
improving application availability. In an ideal situation, an application must be available 24 x 7.
Application availability can be measured as the amount of time that the service is available,
divided by the amount of time in a year, as a percentage.
A PowerHA configuration (also known as a
32) that have their resources managed by PowerHA cluster services. The configuration
provides automated service recovery for the managed applications. Servers can have
physical or virtual I/O resources, or a combination of both.
PowerHA performs the following functions at the cluster level:
Manage and monitor operating system and hardware resources
Manage and monitor application processes
Manage and monitor network resources (service IP addresses)
Automate application control (start/stop/restart/move)
The virtual servers that are defined and managed in zBX use only virtual I/O resources.
PowerHA can manage both physical and virtual I/O resources (virtual storage and virtual
network interface cards).
PowerHA can be configured to perform automated service recovery for the applications that
run in virtual servers that are deployed in zBX. PowerHA automates application failover from
one virtual server in an IBM System p blade to another virtual server in a different System p
blade with a similar configuration.
Failover protects service (masks service interruption) in an unplanned or planned (scheduled)
service interruption. During failover, you might experience a short service unavailability while
resources are configured by PowerHA on the new virtual server.
The PowerHA configuration for the zBX environment is similar to standard Power
environments, except that it uses only virtual I/O resources. Currently, PowerHA for zBX
support is limited to fail over inside the same ensemble. All zBXs participating in the PowerHA
cluster must have access to the same storage.
The PowerHA configuration includes the following tasks:
Network planning (VLAN and IP configuration definition and for server connectivity)
Storage planning (shared storage must be accessible to all blades that provide resources
for a PowerHA cluster)
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Servers can be also virtual servers. One server is one instance of the AIX operating system.
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cluster
) consists of two or more servers
2
(up to