HP-UX 11i Version 2 Release Notes (October 2003)

General System Administration

Compressed Dump

Chapter 4

Compressed Dump

The goal of the Compressed Dump feature is to speed up the memory dump for HP-UX in

the event of a system crash, so that dumps are taken faster and system availability is

improved. This feature is primarily targeted for “large memory machines” running

HP-UX 11i v1, 11i v2, or any later release.

Summary of Change

In HP-UX 11i v2, a new feature has been added to the Dump Subsystem to compress the

physical pages before dumping, resulting in a faster crash dump process.

The following system console interface options have been augmented to manage this new

feature:

crashconf This utility configures system crash dumps on a running system.

savecrash This utility saves the crash dump information of the system (assuming

information was made when the system crashed) and writes a reboot

message in the shutdown log file.

crashutil This utility copies and preserves crash dump data, and performs

format conversions on it.

System crash dumps that are compressed are in a new format called PARDIR. This new

format requires use of new tools and utilities for processing:

• The new crashconf (2) and crashconf (1M) interfaces released with HP-UX 11i v2 are

required to configure for compressed dumps.

• System crash dumps that are in compressed format (PARDIR) require the new

savecrash utility to save the dump from the dump device to the file system.

The dump library libcrash (released with HP-UX 11i v2) should be used to read these

dumps in PARDIR format. To be able to read PARDIR, you must link the kernel debugger

tools q4, adb, and kwdb with libcrash.

Impact

With the Compressed Dump feature, kernel dump+save times are speeded by at least a

factor of 3X. As a consequence, down-time is reduced.

Compatibility

With the utility crashutil (released with HP-UX 11i v2), which can be used to convert

the dump to any of the older formats, older versions of tools can be used with the new

dump format PARDIR.

If uncompressed, the format of system crash dumps will be exactly the same as the

CRASHDIR format and can be processed with the older kernel debugger tools and utilities

savecrash, crashutil, and libcrash.