dump_concurrent_on.5 (2010 09)

d
dump_concurrent_on(5) dump_concurrent_on(5)
(Tunable Kernel Parameters - Integrity Systems Only)
NAME
dump_concurrent_on - enable/disable option for system to dump memory using multiple dump units when
a kernel panic occurs
VALUES
Failsafe
0 disable
Default
1 enable
Allowed values
0 disable multiple dump units (concurrency off)
1 enable multiple dump units (concurrency on)
Recommended value
1 allow the kernel to choose whether or not to dump concurrently
DESCRIPTION
On large systems, the time required to dump system memory when a kernel panic occurs can be excessive
or even prohibitive, depending on how much physical memory is installed in the system. Concurrent
dump capability results in faster dumps by dividing the task to different dump units which can execute in
parallel.
The default value for dump_concurrent_on
is 1. The system determines whether or not to dump
with multiple units based on the resources (CPUs and disks) available on the system and the properties
of the drivers.
The
crashconf (see crashconf (1M)) command and its associated configuration file
/etc/rc.config.d/crashconf
control the dump concurrency mode in the memory dumps associ-
ated with a system crash. On rare occasions, the system may crash before
crashconf is run during the
boot process. On those occasions, the configuration set using the dump_concurrent_on
tunable will
be used.
Who Is Expected to Change This Tunable?
Only HP Field Engineers should change the value of this tunable.
Restrictions on Changing
Changes to this tunable take effect immediately.
When Should the Tunable Be Turned On?
This tunable should be turned on to allow dumps to dump with multiple dump units when there is a sys-
tem crash if there are sufficient resources.
What Are the Side Effects of Turning the Tunable Off?
Dumps may take more time.
When Should the Tunable Be Turned Off?
The tunable should be turned off if there is a problem using multiple dump units.
What Are the Side Effects of Turning the Tunable On?
The system decides whether or not to use multiple dump units based on the resources available.
What Other Tunables Should Be Changed at the Same Time?
None.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parame-
ter values. After installation, some tunable parameters may no longer be at the default or recommended
values. For information about the effects of installation on tunable values, consult the documentation for
the kernel software being installed. For information about optional kernel software that was factory
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1