N+M Cold Standby; Reducing Server Blade Power Consumption; Internal Lan And Management Lan - Hitachi Compute Blade 2500 Getting Started Manual

Related topics
• Preparing the server blades so that they can operate in LP mode on page
3-11

N+M cold standby

N+M cold standby is functionality that, when an active server blade fails,
attempts to reduce the downtime by switching to a standby server blade. The
reliability of the system unit is enhanced by multiplexing the system. Note
that N+M cold standby can be used by linking Hitachi Compute Systems
Manager (HCSM), which is an external server management software, with the
CB 2500.

Reducing server blade power consumption

To reduce power consumption, you can set an upper limit for the power
consumed by the entire server chassis. This is called power capping.
Power capping changes the power state of processors on a server blade, and
reduces power consumption of the server blade. If the CPU workload is low,
the CPU automatically enters the power-saving state.
If the LPAR manager functionality is used and no process to be dispatched
exists, the server blade enters the waiting state until a process to be
dispatched appears. In this state, the power state of the physical processor is
lowered to reduce power consumption. The state in which LPAR manager
functionality is used and no process to be dispatched exists is called a host
idle loop.
Note: If the power capping upper limit is set too low, the CPU performance
might become low and affect OS operation. Thoroughly evaluate the value to
be set to power capping during the operation test before starting the
operation.

Internal LAN and management LAN

Server blades and various modules installed in a server chassis are connected
to a network within the system unit. This network is called the internal LAN. A
management module uses an internal LAN to monitor the statuses of server
blades and various modules, and to communicate control information. The
control information of the system unit is managed by using a network to
connect an external computer and a management module. This network that
manages the system unit is called the management LAN. To use the
management LAN to manage server blades and various modules, you need to
use a management module to specify various network settings when the
system is first set up.
To connect the management LAN and the system unit, you usually use a port
of a management module (management LAN module).
CB 2500 Overview
Hitachi Compute Blade 2500 Series Getting Started Guide
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