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Tunable Kernel Parameters - Integrity Systems Only
HP-UX 11i Version 3: February 2007

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dump_concurrent_on — enable or disable option for system to dump memory using multiple dump units when a kernel panic occurs on Integrity systems



0 disable


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


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 command may also be used to specify whether or not to use multiple dump units. It stores this information in its configuration file /etc/rc.config.d/crashconf.

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 system 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?



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 parameter 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 installed on your system, see HP-UX Release Notes at http://docs.hp.com.


dump_concurrent_on was developed by HP.

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