HP-UX 11i Version 1.5 System Crash Dump

Overview of System Crash Dump

Chapter 1 11

Overview of System Crash Dump

The dump and reboot process is signiﬁcantly faster than in previous

releases of HP-UX, and can handle technologies such as more than 4GB

of physical memory, dynamically loaded kernel modules (DLKM),

non-contiguous physical memory, and the like.

System crash dumps do not contain the entire contents of physical

memory by default. With memory sizes growing in leaps and bounds, it is

critical that only those parts of physical memory which are considered

useful in debugging a problem are dumped. For a discussion of which

parts of memory are dumped, see “Selective Dumps” on page 12.

To simplify access of crash dumps by commands and utilities, HP-UX

provides a crash dump access library, libcrash, which can be used to

access any past-, current-, or future-format dump. For more information,

see “Debugging of Crash Dumps” on page 18.

The system crash dump user interface affords an operator sitting at the

console a limited degree of control of the dump process, plus a great deal

more information about its progress while dumping than was available

in the past. For more information, see “Dump-Time User Interface” on

page 16.

Aside from speeding up the dump process itself, HP-UX speeds up the

process of saving the dump into the ﬁle system after the system has

rebooted. Proper use of the savecrash(1M) and crashutil(1M) utilities,

combined with proper conﬁguration of dump devices, can greatly reduce

or nearly eliminate the time that used to be spent running savecore

(now obsolete) in prior releases. For more information, see “Post-Reboot

Dump Processing” on page 17.

It is not necessary to rebuild the kernel in order to conﬁgure dump

devices: there are several ways of conﬁguring dump devices. Also

described here are the ways to override the defaults for which parts of

memory get included in the dump. For more information, see “Crash

Dump Conﬁguration” on page 13.