IBM Computer Instructions for use

Redbooks Paper
© Copyright IBM Corp. 2005. All rights reserved. ibm.com/redbooks 1
Hardware Management Console
(HMC) Case Configuration Study for
LPAR Management
This IBM® Redpaper provides Hardware Management Console (HMC)
configuration considerations and describes case studies about how to use the
HMC in a production environment. This document does not describe how to
install the HMC or how to set up LPARs. We assume you are familiar with the
HMC. Rather, the case studies presented in this Redpaper provide a framework
to implement some of the more useful HMC concepts. It provides examples to
give you ideas on how to exploit the capabilities of the HMC.
The topics discussed in this Redpaper are:
򐂰Basic HMC considerations
򐂰Partitioning considerations
򐂰Takeover case study:
– Description of the scenario
– Setting up remote ssh connection to the HMC
– Using the HMC to perform CoD operations
– Examples of dynamic LPAR operations
– Using micropartitioning features
– Security considerations
Dino Quintero
Sven Meissner
Andrei Socoliuc

2Hardware Management Console (HMC) Case Configuration Study for LPAR Management
򐂰Automation
򐂰High availability considerations for HMCs
Introduction and overview
The Hardware Management Console (HMC) is a dedicated workstation that
allows you to configure and manage partitions. To perform maintenance
operations, a graphical user interface (GUI) is provided.
Functions performed by the HMC include:
򐂰Creating and maintaining a multiple partition environment
򐂰Displaying a virtual operating system session terminal for each partition
򐂰Displaying a virtual operator panel of contents for each partition
򐂰Detecting, reporting, and storing changes in hardware conditions
򐂰Powering managed systems on and off
򐂰Acting as a service focal point
򐂰Activating CoD
Although this Redpaper contains information relevant to POWER4 systems, our
focus is on the HMC configuration for POWER5 systems. The case studies are
illustrated with POWER5 systems only.
Basic HMC considerations
The Hardware Management Console (HMC) is based on the IBM eServer™
xSeries® hardware architecture running dedicated applications to provide
partition management for single or multiple servers called managed systems.
There are two types of HMCs depending on the CPU architecture of the
managed systems:
򐂰HMC for POWER4 systems
򐂰HMC for POWER5 systems
Table 1 shows the current list of the hardware models for HMCs supported in a
POWER4 or POWER5 environment. The HMCs are available as desktop or
rack-mountable systems.
Note: POWER4™ systems use a serial line to communicate with the HMC.
This has changed with POWER5™. The POWER5 systems use a LAN
connection to communicate with the HMC. POWER4 and POWER5 systems
cannot be managed by the same HMC.

Hardware Management Console (HMC) Case Configuration Study for LPAR Management 3
Table 1 Types of HMCs
The HMC 3.x code version is used for POWER4 managed systems and HMC 4.x
for POWER5 systems (iSeries™ and pSeries®). For managing POWER5
pSeries machines, HMC 4.2 code version or later is required.
Table 2 shows a detailed relationship between the POWER5 pSeries servers and
the supported HMCs.
Table 2 Supported HMCs for pSeries and OpenPower platforms
Type Supported managed
systems HMC code version
7315-CR3 (rack mount) POWER4 or POWER51HMC 3.x, HMC 4.x, or
HMC 5.x
7315-C04 (desktop) POWER4 or POWER51HMC 3.x, HMC 4.x, or
HMC 5.x
7310-CR3 (rack mount) POWER5 HMC 4.x or HMC 5.x
7310-C04 (desktop) POWER5 HMC 4.x or HMC 5.x
1- Licensed Internal Code needed (FC0961) to upgrade these HMCs to manager POWER5 systems. A single
HMC cannot be used to manage a mixed environment of POWER4 and POWER5 systems.
Managed system HMC model supported HMC required
p505 7310-C04 or 7310-CR33No1
p510 7310-C04 or 7310-CR33No1
p520 7310-C04 or 7310-CR33No1
p550 7310-C04 or 7310-CR33No1
p570 7310-C04 or 7310-CR33No1
p575 7310-C04 or 7310-CR33Yes2
p590 7310-C04 or 7310-CR33Yes2
p595 7310-C04 or 7310-CR33Yes2
OpenPower™ 720 7310-C04 or 7310-CR33No1
OpenPower 710 7310-C04 or 7310-CR33No1
1 - An HMC is not required if the system runs in full system partition. For a partitioned
environment an HMC is required.
2- It is recommended to have two HMCs installed for high availability considerations.
3- Previous HMC models with the latest HMC code level are also supported.

4Hardware Management Console (HMC) Case Configuration Study for LPAR Management
The maximum number of HMCs supported by a single POWER5 managed
system is two. The number of LPARs managed by a single HMC has been
increased from earlier versions of the HMC to the current supported release as
shown in Table 3.
Table 3 HMC history
HMC connections
During the installation of the HMC, you have to consider the number of network
adapters required. You can have up to three Ethernet adapters installed on an
HMC. There are several connections you have to consider when planning the
installation of the HMC:
򐂰HMC to the FSP (Flexible Service Processor): It is an IP-based network used
for management functions of the POWER5 systems; for example, power
management and partition management.
POWER5 systems have two interfaces (T1 and T2) available for connections
to the HMC. It is recommended to use both of them for redundant
configuration, and high availability. Depending on your environment, you
have multiple options to configure the network between the HMC and FSP.
The default mechanism for allocation of the IP addresses for the FSP ports is
dynamic. The HMC can be configured as a DHCP server which allocates the
IP address at the time the managed system is powered on. Static IP address
allocation is also an option. You can configure the FSP ports with a static IP
address by using the Advanced System Management Interface (ASMI)
HMC code No. of
HMCs No. of servers No. of LPARs Other information
4.1.x 1 4 40 iSeries Only
4.2.0 2 16 64 p5 520 550 570
4.2.1 2 32 160 OpenPower 720
4.3.1 2 32 254 p5 590 595
4.4.0 2 32 254 p5 575
HMC 7310-CR3/C04
4.5.0 2 32/48 254 48 for non 590/595
5.1.0 2 32/48 254 48 for non 590/595
Note: It is recommended to configure this connection as a private network.

Hardware Management Console (HMC) Case Configuration Study for LPAR Management 5
menus. However not all POWER5 servers support this mechanism of
allocation. Currently p575, p590, and p595 servers support only DHCP.
򐂰HMC to partitions: HMC requires TCP/IP connection to communicate with the
partitions for functions such as dynamic LPAR and Service Focal Point.
򐂰Service Agent (SA) connections: SA is the application running on the HMC for
reporting hardware failures to the IBM support center. It uses a modem for
dial-out connection or an available Internet connection. It can also be used to
transmit service and performance information to IBM and also for CoD
enablement and billing information.
򐂰Remote connection to the HMC using Web-based System Manager (WebSM)
or ssh: For accessing the graphical interface, you can use the WebSM
Remote Client running on UNIX® (AIX® or Linux®) or Windows®. The
command line interface is also available by using the secure shell connection
to the HMC. It can be used by an external management system or a partition
to perform HMC operations remotely.
When planning for the HMC installation also consider that the distance between
the HMC and the managed system must be within 8m (26 ft) distance. The
distance complies with IBM maintenance rules.
Partitioning considerations
With POWER5 systems a greater flexibility was introduced in setting up the
resources of a partition by enabling the Advanced Power Virtualization functions
to provide:
򐂰POWER™ Hypervisor: Supports partitioning and dynamic resource
movement across multiple operating system environments.
򐂰Shared processor LPAR (micro-partitioning): Enables you to allocate less
than a full physical processor to a logical partition.
򐂰Virtual LAN: Provides network Virtualization capabilities that allow you to
prioritize traffic on shared networks.
򐂰Virtual I/O (VIO): Provides the ability to dedicate I/O adapters and devices to
a virtual server, thus allowing the on demand allocation and management of
I/O devices.
򐂰Capacity on Demand (CoD): Allows system resources such as processors
and memory to be activated on an as-needed basis.
򐂰Simultaneous multi-threading (SMT): Allows applications to increase overall
resource utilization by virtualizing multiple physical CPUs through the use of
Note: Either eth0 or eth1 can be a DHCP server on the HMC.

6Hardware Management Console (HMC) Case Configuration Study for LPAR Management
multi-threading. SMT is a feature supported only in AIX 5.3 and Linux at an
appropriate level.
򐂰Multiple operating system support: Logical partitioning allows a single server
to run multiple operating system images concurrently. On a POWER5 system
the following operating systems can be installed: AIX 5L™ Version 5.2 ML4 or
later, SUSE Linux Enterprise Server 9 Service Pack 2, Red Hat Enterprise
Linux ES 4 QU1, and i5/OS.
Additional memory allocation in a partitioned environment
Three memory regions are reserved for the physical memory allocation of a
partition:
򐂰Hypervisor
򐂰Translation control entry (TCE) tables
򐂰Partition page tables
At the beginning of a partition size planning, you have to consider that the
allocated amount of memory in these three regions is not usable for the physical
memory allocation of the partition.
Hypervisor and TCE
All POWER5 systems require the use of the hypervisor. The hypervisor supports
many advanced functions including shared processors, Virtual I/O (VIO),
high-speed communications between partitions using Virtual LAN or concurrent
maintenance. There are many variables that dictate how much hypervisor
memory you will need. It is not a fixed amount of memory as with POWER4
systems.
Also the amount of IO drawers and the different ways to use IO, such as shared
environment, affect the amount of memory the hypervisor uses.
Partition page tables
Partition page tables are set aside in additional memory in the hypervisor to
handle the partition’s memory addressing. The amount of memory the partition
page table reserve depends on the maximum value of the partition, and must be
considered in your partition size planning.
Note: The number of VIOs, the number of partitions, and the number of IO
drawers affect the hypervisor memory.
Note: The bigger the maximum value of a partition, the bigger the amount of
memory not usable for the physical memory allocation of the partition.

Hardware Management Console (HMC) Case Configuration Study for LPAR Management 7
To calculate your desired and maximum memory values accurately, we
recommend that you use the LVT tool. This tool is available at:
http://www.ibm.com/servers/eserver/iseries/lpar/systemdesign.htm
Figure 1 shows an example of how you can use the LPAR validation tool to verify
a memory configuration. In Figure 1, there are 4 partitions (P1..P4) defined on a
p595 system with a total amount of 32 GB of memory.
Figure 1 Using LVT to validate the LPAR configuration

8Hardware Management Console (HMC) Case Configuration Study for LPAR Management
The memory allocated to the hypervisor is 1792 MB. When we change the
maximum memory parameter of partition P3 from 4096 MB to 32768 MB, the
memory allocated to the hypervisor increases to 2004 MB as shown in Figure 2.
Figure 2 Memory used by hypervisor
Figure 3 is another example of using LVT when verifying a wrong memory
configuration. Note that the total amount of allocated memory is 30 GB, but the
maximum limits for the partitions require a larger hypervisor memory.
Figure 3 An example of a wrong memory configuration

Hardware Management Console (HMC) Case Configuration Study for LPAR Management 9
Micro-partitioning
With POWER5 systems, increased flexibility is provided for allocating CPU
resources by using micropartitioning features. The following parameters can be
set up on the HMC:
򐂰Dedicated/shared mode, which allows a partition to allocate either a full CPU
or partial units. The minimum CPU allocation unit for a partition is 0.1.
򐂰Minimum, desired, and maximum limits for the number of CPUs allocated to a
dedicated partition.
򐂰Minimum, desired and maximum limits for processor units and virtual
processors, when using the shared processor pool.
򐂰Capped/uncapped and weight (shared processor mode).
Table 4 summarizes the CPU partitioning parameters with their range values,
and indicates if a parameter can be changed dynamically.
Table 4 Partition parameters
Min/Desired/Max values for CPU, processing units, and virtual processors can
be set only in the partition’s profile. Each time the partition is activated, it tries to
acquire the desired values. A partition cannot be activated if at least the
minimum values of the parameters cannot be satisfied.
Parameter Range Dynamic
LPAR
Capped Capped/uncapped Yes
Weight 0-255 Yes
Processing mode Dedicated/shared No
Processors (dedicated
CPUs) Min-Max Processor1Yes
Processing Units (shared
CPUs) Min-Max Processing units1Yes
Virtual processors Min-Max virtual
processors2Yes
1- Max value is limited by the number of CPUs installed in the system,
including CoD.
2- Between 1 and 64; the min and max allowed values are actually
determined by the min/max of processing units: at least 1 processor for
each 1.0 processing units and max value limited to 10*max processing
units or 64.

10 Hardware Management Console (HMC) Case Configuration Study for LPAR Management
Capacity on Demand
The Capacity on Demand (CoD) for POWER5 systems offers multiple options,
including:
򐂰Permanent Capacity on Demand:
– Provides system upgrades by activating processors and/or memory.
– No special contracts and no monitoring are required.
– Purchase agreement is fulfilled using activation keys.
򐂰On/Off Capacity on Demand:
– Enables the temporary use of a requested number of processors or
amount of memory.
– On a registered system, the customer selects the capacity and activates
the resource.
– Capacity can be turned ON and OFF by the customer; usage information
is reported to IBM.
– This option is post-pay. You are charged at activation.
򐂰Reserve Capacity on Demand:
– Used for processors only.
– Prepaid debit temporary agreement, activated using license keys.
– Adds reserve processor capacity to the shared processor pool, used if the
base shared pool capacity is exceeded.
– Requires AIX 5L Version 5.3 and the Advanced POWER Virtualization
feature.
򐂰Trial Capacity on Demand:
– Tests the effects of additional processors and memory.
– Partial or total activation of installed processors and/or memory.
– Resources are available for a fixed time, and must be returned after trial
period.
– No formal commitment required.
Note: Take into consideration that changes in the profile will not get activated
unless you power off and start up your partition. Rebooting of the operating
system is not sufficient.