Chapter 2. Installation

Compression format for the initrd.img file

In Red Hat Enterprise Linux 6.2, the compression format used for the initrd.img file has changed. The image is now compressed using LZMA rather than Gzip.

To decompress an image, use the xz -d command. For example: 
~]# xz -dc initrd.img | cpio -id
To compress an image, use the xz -9 --format=lzma command. For example: 
~]# find . | cpio -c -o | xz -9 --format=lzma > initrd.img
Support for device identification using WWIDs during installation

Fibre Channel and Serial Attached SCSI (SAS) devices can be now specified by a World Wide Name (WWN) or a World Wide Identifier (WWID) for unattended installations. WWN is part of the IEEE standard which makes it easier to identify storage devices during installation for users utilizing Storage Area Networks (SAN) and other advanced network topologies. When a storage device is attached to a server using multiple physical paths for redundancy or improved performance, WWN for any of these paths is sufficient to identify the device.

Initial RAM disk file

The initial RAM disk file on 64-bit PowerPC and 64-bit IBM POWER Series systems is now named initrd.img. In previous releases, it was named ramdisk.image.gz.

Static IPv6 address support for network installation

In Red Hat Enterprise Linux 6.2, a static IPv6 address can be specified for the ipv6 boot option for network installations. The specified address must be of the following form: 

<IPv6 address>[/<prefix length>]
An example of a valid IPv6 address would then be 3ffe:ffff:0:1::1/128. If the prefix is omitted, the value of 64 is assumed. Specifying a static IPv6 address for the ipv6 boot option complements the already existing dhcp and auto parameters that can be specified for the ipv6 boot option.