Chapter 26. Parameter and Configuration Files The IBM System z architecture can use a customized parameter file to pass boot parameters to the kernel and the installer. This section describes the contents of this parameter file. You need only read this section if you intend to change the shipped parameter file. You need to change the parameter file if you want to: automate the user input for linuxrc or the loader (refer to Chapter 21, Installation Phase 1: Configuring a Network Device and Chapter 22, Installation Phase 2: Configuring Language and Installation Source ). install unattended with kickstart. choose non-default installation settings that are not accessible through the installer"s interactive user interface, such as rescue mode. The parameter file can be used to set up networking non-interactively before the installation program (loader and anaconda ) starts. The kernel parameter file is limited to 895 characters plus an end-of-line character. The parameter file can be variable or fixed record format. Fixed record format increases the file size by padding each line up to the record length. Should you encounter problems with the installer not recognizing all specified parameters in LPAR environments, you can try to put all parameters in one single line or start and end each line with a space character. For more details on kernel parameters and different possibilities of specifying them, see the chapter on booting Linux and the chapter on kernel parameters in Linux on System z Device Drivers, Features, and Commands on Red Hat Enterprise Linux 6 . The parameter file contains kernel parameters, such as root=/dev/ram0 or ro , and parameters for the installation process, such as vncpassword=test or vnc . 26.1. Required Parameters The following parameters are required and must be included in the parameter file. They are also provided in the file generic.prm in directory images/ of the installation DVD: root= file_system where file_system represents the device on which the root file system can be found. For installation purposes, it must be set to /dev/ram0 , which is the ramdisk containing the Red Hat Enterprise Linux installation program. ro mounts the root file system, which is a ramdisk, read-only. ip=off disables automatic network configuration. ramdisk_size= size modifies the memory size reserved for the ramdisk to ensure that the Red Hat Enterprise Linux installation program fits within it. For example: ramdisk_size=40000 . The file generic.prm also contains the additional parameter cio_ignore=all,!0.0.0009 . This setting speeds up boot and device detection on systems with many devices. The installer transparently handles the activation of ignored devices. Important To avoid installation problems arising from cio_ignore support not being implemented throughout the entire stack, adapt the cio_ignore= parameter value to your system or remove the parameter entirely from your parameter file used for booting (IPL) the installer. When installing from an FCP-attached DVD drive, and you encounter a problem with ignored devices, select the menu option clear blacklist in linuxrc (refer to Chapter 21, Installation Phase 1: Configuring a Network Device ) to remove the list of ignored devices.

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