Table of Contents
Advertisement
service threshold (meaning that a service action point has been reached) a request for
service is initiated through an error logging component.
4.4.2 Diagnosing
Using the extensive network of advanced and complementary error detection logic built
directly into hardware, firmware, and operating systems, the IBM Power Systems servers can
perform considerable self-diagnosis.
Boot time
When an IBM Power Systems server powers up, the service processor initializes system
hardware. Boot-time diagnostic testing uses a multitier approach for system validation,
starting with managed low-level diagnostics supplemented with system firmware initialization
and configuration of I/O hardware, followed by OS-initiated software test routines.
Boot-time diagnostic routines include the following elements:
Built-in self-tests (BISTs) for both logic components and arrays ensure the internal
integrity of components. Because the service processor assists in performing these tests,
the system is enabled to perform fault determination and isolation whether or not system
processors are operational. Boot time BISTs might also find faults undetectable by a
processor-based power-on self-test (POST), or through diagnostics.
Wire-tests discover and precisely identify connection faults between components such as
processors, memory, or I/O hub chips.
Initialization of components such as ECC memory, typically by writing patterns of data and
allowing the server to store valid ECC data for each location, can help isolate errors.
To minimize boot time, the system determines which of the diagnostics are required to be
started to ensure correct operation based on the way the system was powered off, or through
the boot-time selection menu.
Run time
All Power Systems servers can monitor critical system components during run time, and they
can take corrective actions when recoverable faults occur. IBM hardware error checking
architecture provides the ability to report non-critical errors in an out-of-band communications
path to the service processor without affecting system performance.
A significant part of IBM runtime diagnostic capability originates with the service processor.
Extensive diagnostic and fault analysis routines have been developed and improved over
many generations of POWER processor-based servers. They enable quick and accurate
predefined responses to both actual and potential system problems. The service processor
correlates and processes runtime error information, using logic derived from IBM engineering
expertise to count recoverable errors (called thresholding) and to predict when corrective
actions must be automatically initiated by the system. This includes the following actions:
Requests for a part to be replaced
Dynamic invocation of built-in redundancy for automatic replacement of a failing part
Dynamic deallocation of failing components so that system availability is maintained
Device drivers
In certain cases, diagnostics are best performed by operating system-specific drivers, most
notably I/O devices that are owned directly by a logical partition. In these cases, the operating
system device driver often works in conjunction with I/O device microcode to isolate and
recover from problems. Potential problems are reported to an operating system device driver,
134
IBM BladeCenter PS703 and PS704 Technical Overview and Introduction
Advertisement
Table of Contents
