Red Hat Enterprise Linux (RHEL) 5.1 or Fedora 7 does not directly support an installation to an NFS-mounted disk. You must create an initial installation on disk. From this initial installation on disk you can create a network installation that can be used by the BladeCenter QS21.
First you install Linux® on the local disk space of a 64-bit POWER-based system. You then copy the resulting root file system to a Network File System (NFS) server where you make it network-bootable and adapt it to the specifics of an individual blade server.
See http://fedoraproject.org/wiki/StatelessLinuxCreateClientImage for general information about installing Linux on diskless systems.
This section describes how you can create a network installation for a single blade server. You can create multiple copies of this first installation and adapt each copy for use by a different blade server. See http://www.ibm.com/alphaworks/tech/dim/ for a description of a tooled approach of managing root file systems and boot kernels for numerous blade servers.