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Chapter 21. Parameter and Configuration Files on IBM Z

The IBM Z architecture can use a customized parameter file to pass boot parameters to the kernel and the installation program. 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:
  • install unattended with Kickstart.
  • choose non-default installation settings that are not accessible through the installation program"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 installation program 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.
The parameter file contains kernel parameters, such as ro, and parameters for the installation process, such as vncpassword=test or vnc.

21.1. 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:
mounts the root file system, which is a RAM disk, read-only.
modifies the memory size reserved for the RAM disk to ensure that the Red Hat Enterprise Linux installation program fits within it. For example: ramdisk_size=40000.
The generic.prm file also contains the additional parameter cio_ignore=all,!condev. This setting speeds up boot and device detection on systems with many devices. The installation program transparently handles the activation of ignored devices.


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 installation program.