Specifications

104 IBM Power 770 and 780 Technical Overview and Introduction
2.12.3 High availability using the HMC
The HMC is an important hardware component. When in operation, POWER7
processor-based servers and their hosted partitions can continue to operate when no HMC is
available. However, in such conditions, certain operations cannot be performed, such as a
DLPAR reconfiguration, a partition migration using PowerVM Live Partition Mobility, or the
creation of a new partition. You might therefore decide to install two HMCs in a redundant
configuration so that one HMC is always operational, even when performing maintenance of
the other one, for example.
If redundant HMC function is desired, a server can be attached to two independent HMCs to
address availability requirements. Both HMCs must have the same level of Hardware
Management Console Licensed Machine Code Version 7 and installed fixes to manage
POWER7 processor-based servers or an environment with a mixture of POWER5,
POWER5+, POWER6, POWER6+, and POWER7 processor-based servers. The HMCs
provide a locking mechanism so that only one HMC at a time has write access to the service
processor. It is recommended that both HMCs are available on a public subnet to allow full
syncronization of functionality. Depending on your environment, you have multiple options to
configure the network.
Note: The service processor is used to monitor and manage the system hardware
resources and devices. The service processor offers two Ethernet 10/100 Mbps ports as
connections. Note the following information:
򐂰 Both Ethernet ports are visible only to the service processor and can be used to attach
the server to an HMC or to access the ASMI options from a client web browser using
the HTTP server integrated into the service processor internal operating system.
򐂰 When not configured otherwise (DHCP or from a previous ASMI setting), both Ethernet
ports of the first FSP have predefined IP addresses:
– Service processor Eth0 or HMC1 port is configured as 169.254.2.147 with netmask
255.255.255.0.
– Service processor Eth1 or HMC2 port is configured as 169.254.3.147 with netmask
255.255.255.0.
For the second FSP of IBM Power 770 and 780, these default addresses are:
– Service processor Eth0 or HMC1 port is configured as 169.254.2.146 with netmask
255.255.255.0.
– Service processor Eth1 or HMC2 port is configured as 169.254.3.146 with netmask
255.255.255.0.
For more information about the service processor, see “Service processor” on page 169.