IBM p5 590 System Handbook page 189

System hang detection
AIX 5L Version 5.1 and higher offers a feature called
that provides a mechanism to detect system hangs and initiates a
pre-configured action. In some situations, it is difficult to distinguish a system
that really hangs (it is not doing any meaningful work anymore) from a system
that is so busy that none of the lower priority tasks, such as user shells, have
a chance to run. The new system hang detection feature uses a shdaemon
entry in the /etc/inittab file with an action field that specifies what should be
done when certain conditions are met.
For more information about how to configure this feature, refer to Managing
AIX Server Farms, SG24-6606.
AIX 5L disk mirroring and LVM sparing
Mirroring the operating system boot disks is a feature available since AIX
Version 4.2.1. It enables continued operation of the system, even in the case
of failure on an operating system disk. Beginning with AIX 5L Version 5.1, it is
possible to designate disks as hot spare disks in a volume group and to
specify a policy to be used in the case of failing disks.
For detailed information about rootvg mirroring on AIX 5L, refer to AIX Logical
Volume Manager, From A to Z: Introduction and Concepts, SG24-5432. For
LVM hot spare disk support in a volume group, refer to AIX 5L Differences
Guide, SG24-5765.
TCP/IP RAS enhancements
Beginning with AIX 5L Version 5.1, AIX 5L provides several availability
features in the TCP/IP network access.
Dead Gateway Detection (DGD)
The
implements a mechanism for hosts to detect a dysfunctional gateway, adjust
its routing table accordingly, and re-route network traffic to an alternate
backup route, if available.
multi-path routing
With the
need to have a different destination, netmask, or group ID lists.
These two features working together enable the system to route TCP/IP traffic
through multiple routes and avoid the defective routes. This is as important as
the server availability itself, because a network failure also causes an interrupt
in server access.
For Ethernet adapters, the
adapters to be grouped together and act as a single interface. In case of a
failure in one interface, another interface will automatically take over the
TCP/IP traffic and continue operation.
For more information about how to configure this feature, refer to Managing
AIX Server Farms, SG24-6606.
feature in AIX 5L Version 5.1
feature in AIX 5L Version 5.1, routes no longer
network interface backup
Chapter 6. Reliability, availability, and serviceability
system hang detection
support allows multiple
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