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.
Performance |
|
Compressed dumps should speed-up the dump and save time by
at least a factor of 3 for all dumps, excluding the UNUSED page
class.
For dumps including the UNUSED page
class, system crash dumps will be at least as fast as uncompressed
dump.
Documentation |
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The following manpages have been updated:
For further information, see the “Compressed Dump” white
paper, available at http://www.docs.hp.com
Obsolescence |
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Not applicable.
Printable version
