zfcpdump: S390 SCSI dump tool (Version 2)
=========================================
zfcpdump is used for creating System dumps for Linux on System z. It has two
parts: a zfcpdump enabled Linux kernel and a userspace application.

This is the 2nd version of zfcpdump, which uses the upstream kernel version
2.6.22 or above, rather than 2.6.12 plus an additional zfcpdump patch, which is
used by version 1.

The userspace application of zfcpdump can reside either in an intitramfs or an
initrd. It reads from zcore/mem, provided by the kernel part, and writes the
system dump to a file on a SCSI disk.

To build a zfcpdump enabled kernel use the following settings in your kernel
configuration:

 * CONFIG_ZFCPDUMP=y
 * Enable ZFCP driver
 * Enable SCSI driver
 * Enable ext2 and ext3 filesystems
 * Disable as many features as possible to keep the kernel small.
   E.g. network support is not needed at all.

You can use the "kernel-2.6.23-zfcpdump.s390(x).config" file as a starting
point for your kernel configuration.

To use the zfcpdump userspace application in an initramfs you need to:

 * Copy the zfcpdump userspace application executable somewhere into your
   Linux tree. E.g. to "arch/s390/boot/zfcpdump. If you do not want to include
   shared libraries in the initramfs, compile the tool with the "-static" gcc
   option.
 * If you want to include e2fsck, which is recommended, add it to your source
   tree, too. The zfcpdump application attempts to start /sbin/e2fsck from the
   ramdisk.
 * Copy the "zfcpdump_initramfs.txt" file to arch/s390/boot
 * Issue "make image" to build the zfcpdump image with initramfs.

In a Linux distribution the zfcpdump enabled kernel image must be copied to
/usr/share/zfcpdump/zfcpdump.image, where the s390 zipl tool is looking for the
dump kernel when preparing a SCSI dump disk.

Automatic build process using initramfs:
========================================
The Makefile in this package can be used to do the build steps automatically.
You have to download the Linux kernel 2.6.23 and the ext2 filesystem utilities
version 1.40 from the respective websites.

 1. Copy linux-2.6.23.tar.bz2 into this directory
 2. Copy e2fsprogs-1.40.tar.gz into this directory
 3. Build zfcpdump.image:
    # make
 4. Install zfcpdump.image:
    # make install

Usage of a ramdisk:
===================
If you decided not to use a built-in initramfs, but use a separate ramdisk
instead, copy your ramdisk to "/usr/share/zfcpdump/zfcpdump.rd".

Additional information:
=======================
For more information on the zfcpdump kernel part please refer to
Documentation/s390/zfcpdump.txt in the vanilla Linux kernel sources.

For more information on how to use zfcpdump and zipl refer to the s390
'Using the Dump Tools' book, which is available from:
http://www.ibm.com/developerworks/linux/linux390.
