IBM AIX Continuous Availability Features - IBM Redbooks

3.1 AIX Reliability, Availability, and Serviceability component
hierarchy
The advanced continuous availability tools and features can be assimilated as Reliability,
Availability, and Serviceability (RAS) tools or facilities. These facilities were developed to
enhance AIX capabilities for investigating application, component or subsystem failures and
problems—without needing to perform a complete system dump or stop the application or
system.
A RAS component hierarchy is used by some features. This divides the system into a
resource hierarchy, and allows individual RAS commands to be directed to very specific parts
of the system. The RAS features that exploit the RAS component hierarchy are runtime
checking, component trace, and component dump. This grouping hierarchy is illustrated in
Figure 3-1.
Figure 3-1 Component Reliability, Availability, and Serviceability
3.1.1 First Failure Data Capture feature
Lightweight memory trace is used to provide information for First Failure Data Capture
(FFDC). It was introduced in AIX Version V5.3 ML3. The set of First Failure Data Capture
features was further expanded in AIX V5.3 TL5 and AIX 6.1. They include:
► Lightweight memory trace (LMT)
► Run-time error checking (RTEC)
► Component Trace (CT)
► Live Dump
These features are enabled by default at levels that provide valuable First Failure Data
Capture information with minimal performance impact. To enable or disable all four advanced
First Failure Data Capture features, enter the following command:
/usr/lib/ras/ffdcctrl -o ffdc=enabled -o bosboot=no
56 IBM AIX Continuous Availability Features
RAS Components
Reliability Availability Serviceability
Runtime Error Checking
CT Private
Buffers
Trace
Light
Weight
Memory
Trace
…
Component RAS …
Component Trace Component Dump
System
Trace
System
Dump
Live Dump