HP-UX System Administrator's Guide: Overview HP-UX 11i v3 (B3921-90011, September 2010)

Partial Save (savecrash -p)
If you have plenty of dump device space but are limited on space in your HP-UX file system,
you can use the -p option to the savecrash command. This command copies only those pages
on dump devices that are endangered by paging activity (the pages residing on devices that are
being used for both paging and dumping). Pages that are on dedicated dump devices are not
copied.
NOTE: It is possible to analyze a crash dump directly from dump devices using a debugger
that supports this feature
7
. But, if you need to save it to removable media or send it to someone
you will first need to copy the memory image to the HP-UX file system area.
For More Information on Defining Dump Devices
The following resources have additional information on defining dump devices:
• The manpage crashconf(1M) describes the primary command used to configure crash dumps.
• The manpage savecrash(1M) describes the various options for saving crash dumps to a file
system area for later analysis or archiving.
• The manpage crashutil(1M) describes the utility for converting crash dumps into various
formats for later analysis. Similar to savecrash, crashutil can also be used to retrieve
crash dump information from raw dump devices into the HP-UX file system area.
• The HP-UX System Administrator's Guide: Routine Management Tasks (Chapter 2: Booting and
Shutdown) has a list of additional relevant manpages in the Configuring Dump Devices
section.
What Happens When the System Crashes
An HP-UX system crash (system panic) is an unusual event. When a panic occurs, it means that
HP-UX encountered a condition that it did not know how to handle (or could not handle).
Sometimes you know right away what caused the crash. Other times the cause is not readily
apparent. It is for this reason that HP-UX is equipped with a dump procedure to capture the
contents of memory at the time of the crash for later analysis.
You define in advance:
• Where you want memory contents dumped (dump devices)
• Whether or not you want the dump to be compressed to save space on your dump devices
(dump compression)
• Whether or not to dump to multiple devices in parallel to save time, allowing (dump
concurrency)
Use the /sbin/crashconf command to configure these options. See the crashconf(1M) for
details on how to configure the various options.
Operator Override Options
When a HP-UX panics, the current dump control option settings are displayed at the system
console during a crash. You then have 10 seconds to interact with the system console before the
current settings are used to proceed with dump processing.
If you choose to interact with the system during the 10-second override period, follow the
on-screen prompts.
7. Analyzing crash dumps is not a trivial task. It requires intimate knowledge of HP-UX internal structures and the
use of debuggers. It is beyond the scope of this document to cover the actual analysis process. If you need help
analyzing a crash dump, contact your HP representative.
Start-up and Shutdown 85