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46.2. Configuring the kdump Service
There are three common means of configuring the
kdumpservice: you can enable and configure it at the first boot, use the Kernel Dump Configuration utility for the graphical user interface, or do so manually on the command line.
A limitation in the current implementation of the
Intel IOMMUdriver can occasionally prevent the
kdumpservice from capturing the core dump image. To use
kdumpon Intel architectures reliably, it is advised that the IOMMU support is disabled.
It is known that the
kdumpservice does not work reliably on certain combinations of HP Smart Array devices and system boards from the same vendor. Consequent to this, users are strongly advised to test the configuration before using it in production environment, and if necessary, configure
kdumpto store the kernel crash dump to a remote machine over a network. For more information on how to test the
kdumpconfiguration, refer to Section 46.2.4, “Testing the Configuration”.
46.2.1. Configuring kdump at First Boot
When the system boots for the first time, the
firstbootapplication is launched to guide the user through the initial configuration of the freshly installed system. To configure
kdump, navigate to the Kdump page and follow the instructions below.
Unless the system has enough memory, the Kdump page will not be available. For information on minimum memory requirements, refer to the Red Hat Enterprise Linux comparison chart. When the
kdumpcrash recovery is enabled, the minimum memory requirements increase by the amount of memory reserved for it. This value is determined by the user and on x86, AMD64, and Intel 64 architectures, it defaults to 128 MB plus 64 MB for each TB of physical memory (that is, a total of 192 MB for a system with 1 TB of physical memory).
Figure 46.1. The kdump configuration screen
126.96.36.199. Enabling the Service
To start the
kdumpdaemon at boot time, select the Enable kdump? checkbox. This will enable the service for runlevels
5, and start it for the current session. Similarly, clearing the checkbox will disable it for all runlevels and stop the service immediately.
188.8.131.52. Configuring the Memory Usage
To configure the amount of memory that is reserved for the
kdumpkernel, click the up and down arrow buttons next to the Kdump Memory field to increase or decrease the value. Notice that the Usable System Memory field changes accordingly showing you the remaining memory that will be available to the system.