  Root RAID HOWTO cookbook
  Michael A. Robinton, michael@bzs.org <mailto:michael@bzs.org>
  v1.06, 12 February 1998

  This document provides a cookbook for creating a root mounted raid
  filesystem and companion fallback rescue system using linux initrd.
  There are complete step-by-step instruction for a raid1 md0 device.
  Each step is accompanied by an explanation of it's purpose.  This pro­
  cedure may be used for all the other raid structures with minor modi­
  fications.

  1.  Introduction

  The reader is assumed to be familiar with the various types of raid
  implementations, their advantages and drawbacks. This is not a
  tutorial, just a set of instructions on how to implement root mounted
  raid on a linux system. All of the information necessary to become
  familiar with linux raid is listed here directly or by reference,
  please read it before send e-mail questions.

  1.1.  Where to get Up-to-date copies of this document.

  Root-RAID-HOWTO

  Available in LaTeX (for DVI and PostScript), plain text, and HTML.

       sunsite.unc.edu/mdw/HOWTO/
       <http://sunsite.unc.edu/mdw/HOWTO/>

  Available in SGML and HTML.

       ftp.bizsystems.com/pub/raid/
       <ftp://ftp.bizsystems.com/pub/raid/>

  1.2.  Bugs

  As of this writing, the problem of stopping a root mounted RAID device
  has not yet been solved in a satisfactory way.  A work-around proposed
  by Ed Welbon and implemented by Bohumil Chalupa is incorporated into
  this document which eliminates the need for a long ckraid at each boot
  for raid1 and raid5 devices. Without the workaround, it is necessary
  to ckraid the md device each time the system is re-booted. On a large
  array this can cause a severe availability performance degradation.
  On my 6 gig RAID1 device running on a Pentium 166 with 128 megs of
  ram, it takes well over half an hour to ckraid :-( after each re-boot.

  The workaround stores the status of the array at shutdown on the real
  boot device and compares it to a reference status placed there when
  the system is first built. If the status's match at reboot, the
  superblock on the array is rebuilt on the next boot, otherwise the
  operator is notified of the status error and the rescue system is left
  running with all the raid tools available.

  Rebuilding the superblock causes the system to ignore that the array
  was powered down without mdstop by marking all the drives as OK, as if
  nothing happened. This only works if all the drives are OK at
  shutdown. If the array was operating with a bad drive, the operator
  must remove the bad drive prior to restarting the md device or the
  data can be corrupted.

  None of this applies to raid0 which does not have to be mdstopped
  before shutdown.
  Final proposed solutions to this problem include a finalrd similar to
  initrd, and mdrootstop which writes the clean flags to the array
  during  shutdown when it is mounted read only. I am sure there are
  others.

  In the mean time, the problem has been by-passed for now Please let me
  know when this problem is solved more cleanly!!!

  1.3.  Acknowledgements

  The writings and e-mail from the following individuals helped to make
  this document possible.  Many of the ideas were stolen from the
  helpful work of others, I have just tried to put it all in COOKBOOK
  form so that it is straightforward to use. My thanks to:

  ·  Linas Vepstas <mailto:linas@linas.org>
      for the RAID howto that explained most of this to me.

  ·  Gadi Oxman <mailto:gadio@netvision.net.il>
      for answering my dumb 'newbie' questions.

  ·  Ed Welbon <mailto:welbon@bga.com>
      for the execellent initrd.md package that inspired me to write
     this.

  ·  Bohumil Chalupa <mailto:bochal@apollo.karlov.mff.cuni.cz>  for
     implementing the re-boot 'workaround' that allows root-mounted-raid
     to work in a production environment.

  ·  and many others who contributed to this work in one way or another.

  1.4.  Copyright Notice

  This document is GNU copyleft by Michael Robinton michael@bzs.org
  <mailto:michael@bzs.org>.

  Permission to use, copy, distribute this document for any purpose is
  hereby granted, provided that the author's / editor's name and this
  notice appear in all copies and/or supporting documents; and that an
  unmodified version of this document is made freely available.  This
  document is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY, either expressed or implied.  While every effort
  has been taken to ensure the accuracy of the information documented
  herein, the author / editor / maintainer assumes NO RESPONSIBILITY for
  any errors, or for any damages, direct or consequential, as a result
  of the use of the information documented herein.

  2.  What you need BEFORE YOU START

  The packages you need and the documentation that answers the most
  common questions about setting up and running raid are listed below.
  Please review them throughly.

  2.1.  Required Packages

  You need to obtain the most recent versions of these packages.

  ·  a linux kernel that supports raid, initrd and /dev/loopx

       I used linux-2.0.32
       <ftp://sunsite.unc.edu/pub/Linux/kernel/> from sunsite
  ·  raid145-971022-2.0.31
     <ftp://ftp.kernel.org/pub/linux/daemons/raid/> patch adds support
     for raid1/4/5

  ·  raidtools-pre3-0.42 <ftp://ftp.kernel.org/pub/linux/daemons/raid/>
     tools to create and maintain raid devices (documentation too).

  ·  linuxthreads-0.71
     <ftp://ftp.inria.fr/INRIA/Projects/cristal/Xavier.Leroy> required
     threads package. Use ftp, browser doesn't work
     ftp.inria.fr/INRIA/Projects/cristal/Xavier.Leroy

  ·  A Linux distribution, ready to install.

       I used Slackware-3.4 <ftp://ftp.cdrom.com/pub/linux> avail­
       able everywhere.

  The detailed instructions in this document are based on the above
  packages.  If the packages have been updated or you use a different
  linux distribution, you may have to modify the procedures you find
  here.

  The patches, tool assortment, etc... may vary with 2.1 kernels.
  Please check the most recent documentation at:

       ftp.kernel.org/pub/linux/daemons/raid/
       <ftp://ftp.kernel.org/pub/linux/daemons/raid/>

  2.2.  Other similar implementations.

  I chose to include in the kernel all of the pieces necessary to run
  from boot without loading any modules.  My kernel image is a little
  over 300k compressed.

  Take a look at Ed Welbon's <mailto:welbon@bga.com> initrd.md.tar.gz
  for another way to make a bootable raid device.  He uses loadable
  modules.  A look at his concise scripts will show you how it is done
  if you need a very small kernel with modules.

       http://www.realtime.net/~welbon/initrd.md.tar.gz
       <http://www.realtime.net/~welbon/initrd.md.tar.gz>

  2.3.  Documentation -- Recommended Reading

  Please read:

       /usr/src/linux/Documentation/initrd.txt

  as well as the documentation and man pages that accompany the
  raidtools set. In particular, read man mdadd as well as the
  QuickStart.RAID document included in the raidtools package.

  2.4.  RAID resources

  ·  sunsite.unc.edu/mdw/HOWTO/mini/Software-RAID
     <http://sunsite.unc.edu/mdw/HOWTO/mini/Software-RAID>

  ·  www.ssc.com/lg/issue17/raid.html
     <http://www.ssc.com/lg/issue17/raid.html>

  ·  linas.org/linux/raid.html <http://linas.org/linux/raid.html>

  ·  ftp.kernel.org/pub/linux/daemons/raid/
     <ftp://ftp.kernel.org/pub/linux/daemons/raid/>

  ·  www.realtime.net/~welbon/initrd.md.tar.gz
     <http://www.realtime.net/~welbon/initrd.md.tar.gz>

  ·  luthien.nuclecu.unam.mx/~miguel/raid/
     <http://luthien.nuclecu.unam.mx/~miguel/raid/>

     Mailing lists can be joined at:

  ·  majordomo@nuclecu.unam.mx <mailto:majordomo@nuclecu.unam.mx> send a
     message to subscribe raiddev

     send mail to: raiddev@nuclecu.unam.mx
     <mailto:raiddev@nuclecu.unam.mx>

  ·  majordomo@vger.rutgers.edu <mailto:majordomo@vger.rutgers.edu> send
     a message to subscribe linux-raid

     send mail to: linux-raid@vger.rutgers.edu <mailto:linux-
     raid@vger.rutgers.edu> (this seems to be the most active list)

  3.  initrd Cookbook for root mounted RAID

  This is the procedure to make an 'initrd' ramdisk with rescue tools
  for raid.

  Specifically, this document referrs to a RAID1 implementation, however
  it is generally applicable to any raid scheme with a root mounted raid
  device.

  3.1.  Security Reminder

  The rescue file system may be used stand alone. Should your raid array
  fail to mount, you are left with the rescue system mounted and
  running.  TAKE THE APPROPRIATE SECURITY PRECAUTIONS!!!

  3.2.  Build the Kernel and Raid Tools

  The first thing that must be done is to patch and build your kernel
  and become familiar with the raid tools.  Configure, mount and test
  your raid device(s). The details of how to do this are included in the
  raidtools package and briefly reviewed later in this document.

  3.3.  Build the initrd Rescue and Boot filesystem

  I used the Slackware-3.4 distribution to build both the Rescue/Boot
  filesystem and the filesystem for the production machine. Any linux
  distribution should work fine. If you use a different distribution,
  review the Slackware specific portion of this procedure and modify it
  to suit your needs.

  You can download the Slackware distribution from:

       ftp.cdrom.com/pub/linux/ <ftp://ftp.cdrom.com/pub/linux/>

  If you already have Slackware, you only need to download new

  I use loadlin to boot the kernel image and ramdisk from a dos
  partition.  I chose to create a minimum ramdisk system using the
  Slackware 'setup' script followed by installing the 'linuxthreads'
  package and 'raidtools' over the clean Slackware installation on my
  ramdisk. I used the identical procedure to build the production
  system. So the rescue and production systems are very similar.

  This installation process gives me a 'bare' system (save a copy of the
  file) to which I overlay

          /lib/modules/2.x.x......
          /etc .... with a modified fstab
          /etc/rc.d
          /dev/md*

  from my current system to customize it for the particular kernel and
  machine that it is/will-be running on.

  This makes the boot/rescue system the same system that is running on
  the root mounted raid device, just skinnyed down a bit, while allowing
  the library, etc... revisions to always be current.

  3.4.  Start the STEP by STEP instructions

  From the root home directory (/root):

          cd /root
          mkdir raidboot
          cd raidboot

  Create a mountpoints to work on

          mkdir mnt
          mkdir mnt2

  Make a file large enough to do the file system install. This will be a
  lot larger than the final rescue file system.  I chose 24 megs since
  16 megs is not large enough

          dd if=/dev/zero of=build bs=1024k count=24

  associate the file with a loop device and generate an ext2 file system
  on the file

          losetup /dev/loop0 build
          mke2fs -v -m0 -L initrd /dev/loop0
          mount /dev/loop0 mnt

  3.5.  Install the distribution - Slackware Specific

  ``...skip Slackware Specific stuff'' and go to next section.

  Now that an empty filesystem is created and mounted, run "setup".

  Specify         /root/raidboot/mnt

  as the 'target'.  The source is whatever you normally install from.
  Select the packages you wish to install and proceed but DO NOT
  configure.

  Choose 'EXPERT' prompting mode.

  I chose 'A', 'AP, and 'N' installing only the minimum to run the
  system plus an editor I am familiar with (vi, jed, joe) that is
  reasonably compact.

  lqqqqqqqq SELECTING PACKAGES FROM SERIES A (BASE LINUX SYSTEM) qqqqqqqqk
  x lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqk x
  x x   [X] aaa_base  Basic filesystem, shell, and utils - REQUIRED    x x
  x x   [X] bash      GNU bash-1.14.7 shell - REQUIRED                 x x
  x x   [X] devs      Device files found in /dev - REQUIRED            x x
  x x   [X] etc       System config files & utilities - REQUIRED       x x
  x x   [X] shadow    Shadow password suite - REQUIRED                 x x
  x x   [ ] ide       Linux 2.0.30 no SCSI (YOU NEED 1 KERNEL)         x x
  x x   [ ] scsi      Linux 2.0.30 with SCSI (YOU NEED 1 KERNEL)       x x
  x x   [ ] modules   Modular Linux device drivers                     x x
  x x   [ ] scsimods  Loadable SCSI device drivers                     x x
  x x   [X] hdsetup   Slackware setup scripts - REQUIRED               x x
  x x   [ ] lilo      Boots Linux (not UMSDOS), DOS, OS/2, etc.        x x
  x x   [ ] bsdlpr    BSD lpr - printer spooling system                x x
  x x   [ ] loadlin   Boots Linux (UMSDOS too!) from MS-DOS            x x
  x x   [ ] pnp       Plug'n'Play configuration tool                   x x
  x x   [ ] umsprogs  Utilities needed to use the UMSDOS filesystem    x x
  x x   [X] sysvinit  System V-like INIT programs - REQUIRED           x x
  x x   [X] bin       GNU fileutils 3.12, elvis, etc. - REQUIRED       x x
  x x   [X] ldso      Dynamic linker/loader - REQUIRED                 x x
  x x   [ ] ibcs2     Runs SCO/SysVr4 binaries                         x x
  x x   [X] less      A text pager utility - REQUIRED                  x x
  x x   [ ] pcmcia    PCMCIA card services support                     x x
  x x   [ ] getty     Getty_ps 2.0.7e - OPTIONAL                       x x
  x x   [X] gzip      The GNU zip compression - REQUIRED               x x
  x x   [X] ps        Displays process info - REQUIRED                 x x
  x x   [X] aoutlibs  a.out shared libs - RECOMMENDED                  x x
  x x   [X] elflibs   The ELF shared C libraries - REQUIRED            x x
  x x   [X] util      Util-linux utilities - REQUIRED                  x x
  x x   [ ] minicom   Serial transfer and modem comm package           x x
  x x   [ ] cpio      The GNU cpio backup/archiving utility            x x
  x x   [X] e2fsbn    Utilities for the ext2 file system               x x
  x x   [X] find      GNU findutils 4.1                                x x
  x x   [X] grep      GNU grep 2.0                                     x x
  x x   [ ] kbd       Change keyboard mappings                         x x
  x x   [X] gpm       Cut and paste text with your mouse               x x
  x x   [X] sh_utils  GNU sh-utils 1.16 - REQUIRED                     x x
  x x   [X] sysklogd  Logs system and kernel messages                  x x
  x x   [X] tar       GNU tar 1.12 - REQUIRED                          x x
  x x   [ ] tcsh      Extended C shell version 6.07                    x x
  x x   [X] txtutils  GNU textutils-1.22 - REQUIRED                    x x
  x x   [ ] zoneinfo  Configures your time zone                        x x
  x mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj x

  From the 'AP series, I use only 'JOE', and editor I like, and 'MC' a
  small and useful file management tool. You choose the utilities you
  will need on your system.

  lqqqqqqqqq SELECTING PACKAGES FROM SERIES AP (APPLICATIONS) qqqqqqqqqk
  x x     [ ] ispell    The International version of ispell          x x
  x x     [ ] jove      Jonathan's Own Version of Emacs text editor  x x
  x x     [ ] manpgs    More man pages (online documentation)        x x
  x x     [ ] diff      GNU diffutils                                x x
  x x     [ ] sudo      Allow special users limited root access      x x
  x x     [ ] ghostscr  GNU Ghostscript version 3.33                 x x
  x x     [ ] gsfonts1  Ghostscript fonts (part one)                 x x
  x x     [ ] gsfonts2  Ghostscript fonts (part two)                 x x
  x x     [ ] gsfonts3  Ghostscript fonts (part three)               x x
  x x     [ ] jed       JED programmer's editor                      x x
  x x     [X] joe       joe text editor, version 2.8                 x x
  x x     [ ] jpeg      JPEG image compression utilities             x x
  x x     [ ] bc        GNU bc - arbitrary precision math language   x x
  x x     [ ] workbone  a text-based audio CD player                 x x
  x x     [X] mc        The Midnight Commander file manager          x x
  x x     [ ] mt_st     mt ported from BSD - controls tape drive     x x
  x x     [ ] groff     GNU troff document formatting system         x x
  x x     [ ] quota     User disk quota utilities                    x x
  x x     [ ] sc        The 'sc' spreadsheet                         x x
  x x     [ ] texinfo   GNU texinfo documentation system             x x
  x x     [ ] vim       Improved vi clone                            x x
  x x     [ ] ash       A small /bin/sh type shell - 62K             x x
  x x     [ ] zsh       Zsh - a custom *nix shell                    x x
  x mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj x

  From the 'N' package I only loaded TCPIP.  This isn't really neces­
  sary, but is very handy and allows access to the network while working
  on a repair or update with the root raid array dismounted. TCPIP also
  contains 'biff' which is used by some of the applications in 'A'. If
  you don't install 'N' you might want to install the biff package any­
  way.

  lqqqq SELECTING PACKAGES FROM SERIES N (NETWORK/NEWS/MAIL/UUCP) qqqqqk
  x lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqk x
  x x    [ ] apache    Apache WWW (HTTP) server                      x x
  x x    [ ] procmail  Mail delivery/filtering utility               x x
  x x    [ ] dip       Handles SLIP/CSLIP connections                x x
  x x    [ ] ppp       Point-to-point protocol                       x x
  x x    [ ] mailx     The mailx mailer                              x x
  x x    [X] tcpip     TCP/IP networking programs                    x x
  x x    [ ] bind      Berkeley Internet Name Domain server          x x
  x x    [ ] rdist     Remote file distribution utility              x x
  x x    [ ] lynx      Text-based World Wide Web browser             x x
  x x    [ ] uucp      Taylor UUCP 1.06.1 with HDB && Taylor configs x x
  x x    [ ] elm       Menu-driven user mail program                 x x
  x x    [ ] pine      Pine menu-driven mail program                 x x
  x x    [ ] sendmail  The sendmail mail transport agent             x x
  x x    [ ] metamail  Metamail multimedia mail extensions           x x
  x x    [ ] smailcfg  Extra configuration files for sendmail        x x
  x x    [ ] cnews     Spools and transmits Usenet news              x x
  x x    [ ] inn       InterNetNews news transport system            x x
  x x    [ ] tin       The 'tin' news reader (local or NNTP)         x x
  x x    [ ] trn       'trn' for /var/spool/news                     x x
  x x    [ ] trn-nntp  'trn' for NNTP (install 1 'trn' maximum)      x x
  x x    [ ] nn-spool  'nn' for /var/spool/news                      x x
  x x    [ ] nn-nntp   'nn' for NNTP (install 1 'nn' maximum)        x x
  x x    [ ] netpipes  Network pipe utilities                        x x
  x mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj x

  With the installation complete, say no to everything else (no to all
  configuration requests) and exit the script.

  3.6.  Install linux pthreads

  Now you must install the 'linuxthreads-0.71' library.  I have included
  this diff for the linuxthreads Makefile rather than explain the
  details of the installation by hand.  Save the original Makefile,
  apply the diff and then:

          cd /usr/src/linuxthreads-0.71
    patch
          make
          make install

  -------------------diff Makefile.old  Makefile.raid-----------------
  2a3,13
  > # If you are building "linuxthreads" for installation on a mount
  > # point which is not the "root" partition, redefine 'BUILDIR' to
  > # the mount point to use as the "root" directory
  > # You may wish to do this if you are building an 'initial ram disk'
  > # such as used with bootable root raid devices.
  > # REQUIRES ldconfig version 1.9.5 or better
  > # do ldconfig -v to check
  > #
  > BUILDIR=/root/raidboot/mnt
  > #BUILDIR=
  >
  81,82c92,93
  <       install pthread.h $(INCLUDEDIR)/pthread.h
  <       install semaphore.h $(INCLUDEDIR)/semaphore.h
  ---
  >       install pthread.h $(BUILDIR)$(INCLUDEDIR)/pthread.h
  >       install semaphore.h $(BUILDIR)$(INCLUDEDIR)/semaphore.h
  84c95
  <       test -f /usr/include/sched.h || install sched.h $(INCLUDEDIR)/sched.h
  ---
  >       test -f $(BUILDIR)/usr/include/sched.h || install sched.h $(BUILDIR)$(INCLUDEDIR)/sched.h
  86,89c97,103
  <       install $(LIB) $(LIBDIR)/$(LIB)
  <       install $(SHLIB) $(SHAREDLIBDIR)/$(SHLIB)
  <       rm -f $(LIBDIR)/$(SHLIB0)
  <       ln -s $(SHAREDLIBDIR)/$(SHLIB) $(LIBDIR)/$(SHLIB0)
  ---
  >       install $(LIB) $(BUILDIR)$(LIBDIR)/$(LIB)
  >       install $(SHLIB) $(BUILDIR)$(SHAREDLIBDIR)/$(SHLIB)
  >       rm -f $(BUILDIR)$(LIBDIR)/$(SHLIB0)
  >       ln -s $(SHAREDLIBDIR)/$(SHLIB) $(BUILDIR)$(LIBDIR)/$(SHLIB0)
  > ifneq ($(BUILDIR),)
  >       ldconfig -r ${BUILDIR} -n $(SHAREDLIBDIR)
  > else
  91c105,106
  <       cd man; $(MAKE) MANDIR=$(MANDIR) install
  ---
  > endif
  >       cd man; $(MAKE) MANDIR=$(BUILDIR)$(MANDIR) install

  3.7.  Install Raid Tools

  The next step is the installation of the raid tools.  raidtools-0.42

  You must run the "configure" script to point the Makefile at the build
  directory for the ramdisk files

    cd /usr/src/raidtools-0.42
    configure --sbindir=/root/raidboot/mnt/sbin --prefix=/root/raidboot/mnt/usr
    make
    make install

  Now!! the Makefile for install is not quite right so do the following
  to clean up. This will be fixed in future releases so that the re-
  linking will not be necessary.

       Fix the make install error

  The file links specified in the Makefile at 'LINKS' must be removed
  and re-linked to operate properly.

          cd /root/raidboot/mnt/sbin
          ln -fs mdadd mdrun
          ln -fs mdadd mdstop

  3.8.  Remove un-needed directories and files from new filesystem.

  Delete the following directories from filesystem (CAUTION DON'T DELETE
  FROM YOUR RUNNING SYSTEM) it's easy to do, guess how I found out!!!

          cd /root/raidboot/mnt
          rm -r home/ftp/*
          rm -r lost+found
          rm -r usr/doc
          rm -r usr/info
          rm -r usr/local/man
          rm -r usr/man
          rm -r usr/openwin
          rm -r usr/share/locale
          rm -r usr/X*
          rm -r var/man
          rm -r var/log/packages
          rm -r var/log/setup
          rm -r var/log/disk_contents

  3.9.  Create /dev/mdx

  The last step simply copies the /dev/md* devices from the current file
  system onto the rescue file system.  You could create these with
  mknode.

          cp -a /dev/md* /root/raidboot/mnt/dev

  3.10.  Create a bare filesystem suitable for initrd

  Now you have a clean re-useable filesystem ready for customization.
  Once customized, this file system can be used for rescue should the
  raid device(s) become corrupted and the raid tools needed to fix them.
  It will also be used to boot and root-mount the raid device by adding
  the linuxrc file which will be discussed next.

  Copy the file system to a smaller device for the initrd file, 16 megs
  should be large enough.

  Create the smaller file system and mount it

          cd /root/raidboot
          dd if=/dev/zero of=bare.fs bs=1024k count=16

  associate the file with a loop device and generate a ext2 file system
  on the file

          losetup /dev/loop1 bare.fs
          mke2fs -v -m0 -L initrd /dev/loop1
          mount /dev/loop1 mnt2

  Copy the 'build' file system to 'bare.fs'

          cp -a mnt/* mnt2

  Save the 'bare.fs' system before customization so later update is
  easy.  The 'build' file system is no longer needed and may be deleted.

          cd /root/raidboot
          umount mnt
          umount mnt2
          losetup -d /dev/loop0
          losetup -d /dev/loop1
          rm build
          cp bare.fs rescue
          gzip -9 bare.fs

  3.10.1.  Create the BOOT/RESCUE initrd filesystem

  Now copy the system dependent items that match the kernel from the
  development platform, or you can manually modify the files in the
  rescue file system to match your target system.

          losetup /dev/loop0 rescue
          mount /dev/loop0 mnt

  Make sure your etc directory is clean of *~, core and log files.  The
  next 2 commands creates some warning messages, ignore them.

          cp -dp /etc/* mnt/etc
          cp -dp /etc/rc.d/* mnt/etc/rc.d

          mkdir  mnt/lib/modules
          cp -a  /lib/modules/2.x.x mnt/lib/modules <--- your current 2.x.x

  Edit the following files to correct them for your rescue system.

          cd mnt

  Non-network
          etc/fstab       comment out the mount of root and raid devices.
          etc/mdtab       should work OK
  Network
          etc/hosts
          etc/resolv.conf
          etc/hosts.equiv         and related files
          etc/rc.d/rc.inet1       correct ip#, mask, gateway, etc...
          etc/rc.d/rc.S           remove entire section on file system status
                  from:
                          # Test to see if the root partition isread-only
                  to but not including:
                          # remove /etc/mtab* so that mount will .....
                                  This avoids the annoying warning that
                                  the ramdisk is mounted rw.
          etc/rc.d/rc.xxxxx       others as required, see later on in this doc
          root/.rhosts            if present
          home/xxxx/xxxx          others as required

      WARNING:    The above procedure moves your password and shadow
                  files onto the rescue disk!!!!!

      WARNING:    You may not wish to do this for security reasons.

  Create any directories for mounting /dev/disk... as may be required
  that are unique to your system.  Mine need:

          cd /root/raidboot/mnt           <--- initrd root
          mkdir dosa                      dos partition mount point
          mkdir dosc                      dos mirror mount point

  The rescue file system is complete!

  You will note upon examination of the files in the rescue file system,
  that there are still many files that could be deleted.  I have not
  done this since it would overly complicate this procedure and most
  raid systems have adequate disk and memory.  If you wish to skinny
  down the file system, go to it!

  3.10.2.  Making initrd boot the RAID device - linuxrc

  To make the rescue disk boot the raid device, you need only copy the
  executable script file:

       linuxrc

  to the root of the device.

  ---------------------- linuxrc --------------------
  #!/bin/sh
  # ver 1.07 2-12-98
  # mount the proc file system
  /bin/mount /proc

  # This may vary for your system.
  # Mount the dos partitions, try both
  # in case one disk is dead
  /bin/mount /dosa
  /bin/mount /dosc

  # Set a flag in case the raid status file is not found
  # then check both drives for the status file
  RAIDOWN="raidstat.ro not found"
  /bin/echo "Reading md0 shutdown status."
  if [ -f /dosa/linux/raidstat.ro ]; then
    RAIDOWN=`/bin/cat /dosa/linux/raidstat.ro`
    RAIDREF=`/bin/cat /dosc/linux/raidgood.ref`
  else
    if [ -f /dosc/linux/raidstat.ro ]; then
      RAIDOWN=`/bin/cat /dosc/linux/raidstat.ro`
      RAIDREF=`/bin/cat /dosc/linux/raidgood.ref`
    fi
  fi

  # Test for a clean shutdown with all disks operational
  if [ "${RAIDOWN} != ${RAIDREF}" ]; then
    echo "ERROR ${RAIDOWN}"
  #  Use the next 2 lines to BAIL OUT and leave rescue running
     /bin/echo 0x100>/proc/sys/kernel/real-root-dev
     exit                 # leaving the error files in dosa/linux,etc...
  fi

  # The raid array is clean, proceed by removing
  # status file and writing a clean superblock
  /bin/rm /dosa/linux/raidstat.ro
  /bin/rm /dosc/linux/raidstat.ro
  /sbin/mkraid /etc/raid1.conf -f --only-superblock

  /bin/umount /dosa
  /bin/umount /dosc

  # Mount raid array
  echo "Mounting md0, root filesystem"
  /sbin/mdadd -ar

  #  If there are errors - BAIL OUT and leave rescue running
  if [ $? -ne 0 ]; then
     echo "RAID device has errors"
  #  Use the next 3 lines to BAIL OUT
     /bin/rm /etc/mtab            # remove bad mtab
     /bin/echo 0x100>/proc/sys/kernel/real-root-dev
     exit
  fi

  # else tell the kernel to switch to /dev/md0 as the /root device
  # The 0x900 value the device number calculated by:
  #  256*major_device_number + minor_device number
  /bin/echo 0x900>/proc/sys/kernel/real-root-dev

  # umount /proc to deallocate initrd device ram space
  /bin/umount /proc
  /bin/echo "/dev/md0 mounted as root"
  exit
  #------------------ end linuxrc ----------------------
  Add 'linuxrc' to initrd boot device

          cd /root/raidboot
          chmod 777 linuxrc
          cp -p linuxrc mnt

  3.11.  Modifying the rc-scripts for SHUTDOWN

  To complete the installation, modify the rc scripts to save the md
  status to the real root device when shutdown occurs.

  In slackware this is rc.0 -> rc.6

  I have modified Bohumil Chalupa's raid stop work-around slightly. His
  original solution is presented in ``Appendix A''.

  Since there are no linux partitions left on the production system
  except md0, the dos partitions are used to store the raidOK readonly
  status.  I chose to write a file to each dos partition containing the
  status of the md array at shutdown and signifying that the md device
  has been remounted RO. This allows the system to be fail safe when one
  of the hard drives dies.

  I modified my rc.6 script to attempt dismount of the root raid1 array
  and any other raid device in mdtab. You may need slightly different
  scripts, but the basics should be the same. The complete rc.6 file is
  shown in ``Appendix B''.

  To capture the raid array shutdown status, just before the file
  systems are dismounted insert:

          RAIDSTATUS=`/bin/cat /proc/mdstat | /usr/bin/grep md0`

  After all the file systems are dismounted (the root file system

          # root device remains mounted RO
          # mount dos file systems RW
          mount -n -o remount,ro /
          echo "Writing RAID read-only boot FLAG(s)."
          mount -n /dosa
          mount -n /dosc
          # create raid mounted RO flag in duplicate
          # containing the shutdown status of the raid array
          echo ${RAIDSTATUS} > /dosa/linux/raidstat.ro
          echo ${RAIDSTATUS} > /dosc/linux/raidstat.ro

          umount -n /dosa
          umount -n /dosc

          # Stop all the raid arrays (except root)
          echo "Stopping raid"
          mdstop -a

  This will cleanly stop all raid devices except root.  Root status is
  passed to the next boot in raidstat.ro.

  Copy the rc file to your new raid array, the rescue file system that
  is still mounted on /root/raidboot/mnt and the development system if
  it is on the same machine.

  Modify rescue etc/fstab as needed and make sure rescue mdtab is
  correct.

  Now copy the rescue disk to your dos partition and everything should
  be ready to boot the raid device as root.

          umount mnt
          losetup -d /dev/loop0
          gzip -9 rescue

  Copy rescue.gz to your dos partition.

  All that remains is to test the new file system  by rebooting.  See
  the loadlin parameters in my dos linux.bat file next.

  3.12.  Setting up loadlin boot for RESCUE and RAID

  The disks I chose for my system are much larger than those manageable
  by lilo. Therefore, I used loadlin to boot the system from a small dos
  partition with a mirror (copy) on the companion disk.

  My dos root system contains a small editor among the utilities so I
  can modify the boot parameters of loadlin if necessary, allowing me to
  reboot the linux system on my swap disk while testing.

  The dos system contains this tree for linux"

          c:\linux.bat
          c:\linux\loadlin.exe
          c:\linux\zimage
          c:\linux\rescue.gz
          c:\linux\raidgood.ref
          c:\linux\raidstat.ro    (only at shutdown)

  ---------------------- linux.bat ---------------------------
  rem  Sample DOS batch file to boot Linux.
  rem  Start the LOADLIN process:

  rem c:\linux\loadlin c:\linux\zimage root=/dev/ram0 ro ramdisk_size=16384 initrd=c:\linux\rescue.gz mem=131072k
  c:\linux\loadlin c:\linux\zimage root=/dev/md0 ro ramdisk_size=16384 initrd=c:\linux\rescue.gz mem=131072k

  rem -- this is my development system -- it goes away later
  rem c:\linux\loadlin c:\linux\zimage root=/dev/hda3 ro noinitrd mem=131072k
  ------------------------------------------------------------

  ***** >> NOTE!! the only difference between forcing the rescue system to
              run and the raid device mounting, is the loadlin parameter

                  root=/dev/ram0          for the rescue system
                  root=/dev/md0           for RAID

                  With root=/dev/ram0 the RAID device will not mount
                  and the rescue system will run unconditionally.

  If the RAID array fails, the rescue system is left mounted and running
  (this seems to fail sometimes, I don't know why, it works when the
  reset button is pushed but does not work with 'shutdown -r now').

  4.  Configuring the Production RAID system.

  4.1.  System specs.

  Motherboard:    Iwill P55TU     dual ide + adaptec scsi
  Processor:      Intel P200
  Disks:          2 ea. Maxtor 7 gig eide

  The disk drives are designated by linux as 'hda' and 'hdc'

  4.2.  Partitioning the hard drives.

  Since testing a large root mountable RAID array is difficult because
  of the re-boot problem, I re-partitioned my swap space to include a
  smaller RAID partition for testing purposes.  You may find this
  helpful.

          <bf/DEVELOPMENT SYSTEM/

    /dev/hda1     dos             16meg
  * /dev/hda2     extended        126m
    /dev/hda3     linux           126m    root partition during development
    /dev/hda4     linux           6+gig   raid1
  * /dev/hda5     linux            26m    test raid1
  * /dev/hda6     linux swap      100m

    /dev/hdc1     is simply an exact copy of hda1 so the
                  partion can be made active if hda fails
  * /dev/hdc2     extended        126m
    /dev/hdc3     linux           126m    /usr/src  during development
    /dev/hdc4     linux           6+gig   raid1 mirror
  * /dev/hdc5     linux            26m    test raid1 mirror
  * /dev/hdc6     linux swap      100m

          <bf/PRODUCTION SYSTEM/

  /dev/hda1       dos             16meg
  /dev/hda2       linux swap      126m
  /dev/hda3       linux swap      126m
  /dev/hda4       linux           6+gig   raid1

  /dev/hdc1       is simply an exact copy of hda1
  /dev/hdc2       linux swap      126m
  /dev/hdc3       linux swap      126m
  /dev/hdc4       linux           6+gig   raid1 mirror

  The hdx3 partitions were switched to 'swap' after developing this
  utility. I could have done it on another machine, however, the
  libraries and kernels are all about a year or more out of date on my
  other linux boxes and I preferred to build it on the target machine.

  I chose to partition this way and use lodlin rather than lilo because

  1. The main partition (6 gig) is to large to accomodate booting with
     lilo alone and would have required an additional smaller partition
     located within the first 1024 disk addresses.

  2. In the event that one drive fails catastrophically, the system must
     continue to run and be bootable with minimum effort and NO data
     loss.
  ·  If either hard drive fails, the boot will abort, and the rescue
     system will run. Examination of the screen message or
     /dosx/linux/raidstat.ro will tell the operator the status of the
     failed array.

  ·  If hda fails, the dos partition on hdc must be made 'active' and
     the bios must recognize hdc as the boot device or it must be
     physically be moved to the hda position by re-cableing.  The raid
     system can then be made active again by removing the failed drive
     and issuing:

              "/sbin/mkraid /etc/raid1.conf -f --only-superblock"

  to rebuild the remaining superblock.

  ·  Once this is done, then

             mdadd -ar

  ·  Examine the status of the array to verify that everything is OK
     then replace the good array reference with the current status until
     the failed disk can be repaired or replaced.

             cat /proc/mdstat | grep md0 > /dosa/linux/raidgood.ref

             shutdown -r now

  to do a clean reboot, and the system is up again.

  5.  Building the RAID file system.

  This description is for my RAID1 system described in the system specs.
  Your system may have a different RAID architecture, so modify as
  appropriate. Please read the man pages and QuickStart.RAID that come
  with the raidtools-0.42 My /etc/raid1.conf contains:

          # raid-1 configuration
          raiddev                 /dev/md0
          raid-level              1
          nr-raid-disks           2
          nr-spare-disks          0

          device                  /dev/hda4
          raid-disk               0

          device                  /dev/hdc4
          raid-disk               1

  5.1.  Step by Step procedures for building production RAID file sys­
  tem.

  For my RAID1 system I did a complete install of:

          Slackware-3.4
          linuxthreads-0.71
          raidtools-0.42
          linux-2.0.32 with raid145 patch

  Create and format the raid device.

          mkraid /etc/raid1.conf
          mdcreate raid1 /dev/md0 /dev/hda4 /dev/hdc4
          mdadd -ar
          mke2fs /dev/md0
          mkdir /md
          mount -t ext2 /dev/md0 /md

  Create the reference files that reboot will use, this may be different
  on your system.

          cat /proc/mdstat | grep md0 > /dosa/linux/raidgood.ref
          cat /proc/mdstat | grep md0 > /dosc/linux/raidgood.ref

  Use Slackware-3.4 or another distribution to build your OS

          setup

  Specify '/md' as the target, and the source whatever your normally
  use.  Select and install the disksets of interest except for the ker­
  nel.  Configure the system, but skip the section on lilo and kernel
  booting.  Exit setup.

  Install 'pthreads'

          cd /usr/src/linuxthreads-0.71

  edit the Makefile and specify

          BUILDIR=/md

          make
          make install

  Install 'raidtools'

          cd /usr/src/raidtools-0.42
          configure --sbindir=/md/sbin --prefix=/md/usr

  fix the raidtools make install error

          cd /md/sbin
          rm mdrun
          rm mdstop
          ln -s mdadd mdrun
          ln -s mdadd mdstop

  Create /dev/mdx

          cp -a /dev/md* /md/dev

  Add the system configuration from the current system (ignore errors).

          cp -dp /etc/* mnt/etc
          cp -dp /etc/rc.d/* mnt/etc/rc.d         (include the new rc.6)
          mkdir  mnt/lib/modules
          cp -a  /lib/modules/2.x.x mnt/lib/modules <--- your current 2.x.x

  Edit the following files to correct them for your file system

          cd /md

  Non-network
          etc/fstab       correct for real root and raid devices.
          etc/mdtab       should work OK
  Network
          etc/hosts
          etc/resolv.conf
          etc/hosts.equiv         and related files
          etc/rc.d/rc.inet1       correct ip#, mask, gateway, etc...
          etc/rc.d/rc.S           remove entire section on file system status
                  from:
                          # Test to see if the root partition isread-only
                  to but not including:
                          # remove /etc/mtab* so that mount will .....
                                  This avoids the annoying warning that
                                  the ramdisk is mounted rw.
          etc/rc.d/rc.xxxxx       others as required
          root/.rhosts            if present
          home/xxxx/xxxx          others as required

      WARNING:    The above procedure moves your password and shadow
                  files onto the new file system!!!!!

      WARNING:    You may not wish to do this for security reasons.

  Create any directories for mounting /dev/disk... as may be required
  that are unique to your system.  Mine need:

          cd /md          <--- new file system root
          mkdir dosa                      dos partition mount point
          mkdir dosc                      dos mirror mount point

  The new file system is complete. Make sure and save the md reference
  status to the 'real' root device and you are ready to boot.

  mount the dos partitions on dosa and dosc

          cat /proc/mdstat | grep md0 > /dosa/linux/raidgood.ref
          cat /proc/mdstat | grep md0 > /dosc/linux/raidgood.ref

          mdstop /dev/md0

  6.  One last thought.

  Remember that an expert is someone who knows at least 1% more than you
  do about a subject.  Bear this in mind when you e-mail me for help.
  I'll try, but I've only done this once!

  Michael Robinton Michael@bzs.org <mailto:michael@bzs.org>

  7.  Appendix A. - Bohumil Chalupa's md0 shutdown

  Bohumil Chalupa's post to the linux raid list on the work around for
  the raid1 + 5 mdstop problem. His solution does not address the
  possibility of the raid device being corrupt at shutdown.  So I have
  added a simple status comparison to a good reference status at boot.
  This allows the operator to intervene if something is wrong with a
  disk in the array. The description of this is in the main body of this
  document.

  > From: Bohumil Chalupa <bochal@apollo.karlov.mff.cuni.cz>
  >
  > I can now boot initrd and use linuxrc to start the RAID1 array,
  > then successfully switch root to /dev/md0.
  >
  > I don't know, however, any way how to cleanly _stop_ the array.

  Well. I have to answer myself :-)

  > Date: Mon, 29 Dec 1997 02:21:38 -0600 (CST)
  > From: Edward Welbon <welbon@bga.com>
  > Subject: Re: dismounting root raid device
  >
  > For md devices other than raid0, there is probably state that needs to
  > be saved that is only known once all writes have completed.  Such state
  > of course can't be saved to root once it is mounted readonly.  In that
  > case, you would have to be able to mount a writeable filesystem "X"
  > on the readonly root and be able to write to "X" (I recall doing this
  > during "rescue" operations, but not as an automated procedure).
  >
  > The filesystem "X" would presumably be a boot device from which the raid
  > (during linuxrc exection via initrd) would pickup it's initial state from.
  > Fortunately raid0 isn't required to write out any state (though it would
  > be pleasant to be able to write the check sums to mdtab after an mdstop).
  > Eventually, I will fiddle with this but it doesn't seem difficult though
  > the "devil" is always in the "details".

  Yes, that's it.
  I had this idea in mind for some time already, but had no time to try it.
  Yesterday I did, and it works.

  With my RAID1 (mirror), I don't save any checksums or raid superblock data.
  I only save an information on the "real" boot partition, that the root md
  volume was remounted readonly during shutdown. Then, during boot, the
  linuxrc script runs mkraid --only-superblock  when it finds this
  information; otherwise, it runs ckraid.
  This means, that the raid superblock information is not updated during
  shutdown; it's updated at the boot time.
  It is not very clean, I'm afraid,  :-(   but it works.

  I'm using Slackware and initrd.md by Edward Welbon to boot the root raid
  device.
  As far as I remember now, the only modified files are
  mkdisk and linuxrc, and /etc/rc.d/rc.6 shutdown script.
  And lilo.conf, of course.

  I'm appending the important parts.

  Bohumil Chalupa

  --------------- my.linuxrc follows -----------------
  #!/bin/sh
  # we need /proc
  /bin/mount /proc
  # start up the md0 device. let the /etc/rc.d scripts get the rest of them
  # we should do as little as possible here
  # ________________________________________
  # root raid1 shutdown test & recreation
  # /start must be created on the rd image in my.mkdisk
  echo "preparing md0: mounting /start"
  /bin/mount /dev/sda2 /start -t ext2
  echo "reading saved md0 state from /start"
  if [ -f /start/root.raid.ok ]; then
   echo "raid ok, modyfying superblock"
   rm /start/root.raid.ok
   /sbin/mkraid /etc/raid1.conf -f --only-superblock
  else
   echo "raid not clean, runing ckraid --fix"
   /sbin/ckraid --fix /etc/raid1.conf
  fi
  echo "unmounting /start"
  /bin/umount /start
  # _________________________________________
  #
  echo "adding md0 for root file system"
  /sbin/mdadd /dev/md0 /dev/sda1 /dev/sdb1
  echo "starting md0"
  /sbin/mdrun -p1 /dev/md0
  # tell kernel we want to switch to /dev/md0 as root device, the 0x900 value
  # is arrived at via 256*major_device_number + minor_device number.
  echo "setting real-root-dev"
  /bin/echo 0x900>/proc/sys/kernel/real-root-dev
  #  unmount /proc so that the ram disk can be deallocated.
  echo "unmounting /proc"
  /bin/umount /proc
  /bin/echo "We are hopefully ready to mount /dev/md0 (major 9, minor 0) as
  root"
  exit
  --------------- end of my.linuxrc ----------------------------------

  ----------- extract from /etc/rc.d/rc.6 follows -----------------
    # Turn off swap, then unmount local file systems.
    echo "Turning off swap."
    swapoff -a
    echo "Unmounting local file systems."
    umount -a -tnonfs
    # Don't remount UMSDOS root volumes:
    if [ ! "`mount | head -1 | cut -d ' ' -f 5`" = "umsdos" ]; then
      mount -n -o remount,ro /
    fi

    # Save raid state
    echo "Saving RAID state"
    /bin/mount -n /dev/sda2 /start -t ext2
    touch /start/root.raid.ok
    /bin/umount -n /start

  -------------- end of excerpt from rc.6 ------------------------

  ------------------ part of my.mkdisk follows ----------------------
  #
  #  now we have the filesystem ready to be populated, we need to
  #  get a few important directories.  I had endless trouble till
  #  I created a pristine mtab.  In my case, it is convenient that
  #  /etc/mdtab is copied over, this way I can activate md with
  #  a simple "/sbin/mdadd -ar" in linuxrc.
  #
  cp -a $ROOT/etc $MOUNTPNT 2>cp.stderr 1>cp.stdout
  rm -rf $MOUNTPNT/etc/mtab
  rm -rf $MOUNTPNT/etc/ppp*
  rm -rf $MOUNTPNT/etc/termcap
  rm -rf $MOUNTPNT/etc/sendmail*
  rm -rf $MOUNTPNT/etc/rc.d
  rm -rf $MOUNTPNT/etc/dos*
  cp -a $ROOT/sbin $ROOT/dev $ROOT/lib $ROOT/bin $MOUNTPNT 2>>cp.stderr
  1>>cp.stdout
  # _____________________________________________________________________
  #  RAID: will need mkraid and ckraid
  cp -a $ROOT/usr/sbin/mkraid $ROOT/usr/sbin/ckraid $MOUNTPNT/sbin
  2>>cp.stderr 1>>cp.stdout
  # ---------------------------------------------------------------------
  #  it seems that init wont come out to play unless it has utmp.   this can
  #  probably be pruned back alot.  no telling what the real bug was 8-).
  #
  mkdir $MOUNTPNT/var $MOUNTPNT/var/log $MOUNTPNT/var/run $MOUNTPNT/initrd
  touch $MOUNTPNT/var/run/utmp $MOUNTPNT/etc/mtab
  chmod a+r $MOUNTPNT/var/run/utmp $MOUNTPNT/etc/mtab
  ln -s /var/run/utmp $MOUNTPNT/var/log/utmp
  ln -s /var/log/utmp $MOUNTPNT/etc/utmp
  ls -lstrd $MOUNTPNT/etc/utmp $MOUNTPNT/var/log/utmp $MOUNTPNT/var/run/utmp
  #
  #  since I wanted to change the mount point, I needed this though
  #  I suppose that I could have done a "mkdir /proc" in linuxrc.
  #
  mkdir $MOUNTPNT/proc
  chmod 555 $MOUNTPNT/proc
  #
  #  ------------------------------------------------------
  #  we'll mount the real boot device to /start temporarily
  #  to check the root raid state saved at shutdown time
  #
  mkdir $MOUNTPNT/start
  #  -------------------------------------------------------
  #
  #  need linuxrc  (it is, after all, the point of this exercise).
  #
  if [ -x ./my.linuxrc ]; then
    cp -a ./my.linuxrc $MOUNTPNT/linuxrc
    chmod 777 $MOUNTPNT/linuxrc
  else
     ln -s /bin/sh $MOUNTPNT/linuxrc
  fi
  #
  ----------------- part of my.mkdisk ends -----------------

  8.  Appendix B. - complete rc.0 -> rc.6 file

  #! /bin/sh
  #
  # rc.6          This file is executed by init when it goes into runlevel
  #               0 (halt) or runlevel 6 (reboot). It kills all processes,
  #               unmounts file systems and then either halts or reboots.
  #
  # Version:      @(#)/etc/rc.d/rc.6      1.50    1994-01-15
  #
  # Author:       Miquel van Smoorenburg <miquels@drinkel.nl.mugnet.org>
  # Modified by:  Patrick J. Volkerding, <volkerdi@ftp.cdrom.com>
  # Modified by:  Michael A. Robinton, <michael@bzs.org> for RAID shutdown

    # Set the path.
    PATH=/sbin:/etc:/bin:/usr/bin

    # Set linefeed mode to avoid staircase effect.
    stty onlcr

    echo "Running shutdown script $0:"

    # Find out how we were called.
    case "$0" in
          *0)
                  message="The system is halted."
                  command="halt"
                  ;;
          *6)
                  message="Rebooting."
                  command=reboot
                  ;;
          *)
                  echo "$0: call me as \"rc.0\" or \"rc.6\" please!"
                  exit 1
                  ;;
    esac

    # Kill all processes.
    # INIT is supposed to handle this entirely now, but this didn't always
    # work correctly without this second pass at killing off the processes.
    # Since INIT already notified the user that processes were being killed,
    # we'll avoid echoing this info this time around.
    if [ "$1" != "fast" ]; then # shutdown did not already kill all processes
      killall5 -15
      killall5 -9
    fi

    # Try to turn off quota and accounting.
    if [ -x /usr/sbin/quotaoff ]
    then
          echo "Turning off quota."
          /usr/sbin/quotaoff -a
    fi
    if [ -x /sbin/accton ]
    then
          echo "Turning off accounting."
          /sbin/accton
    fi

    # Before unmounting file systems write a reboot or halt record to wtmp.
    $command -w

    # Save localtime
    [ -e /usr/lib/zoneinfo/localtime ] && cp /usr/lib/zoneinfo/localtime /etc

    # Asynchronously unmount any remote filesystems:
    echo "Unmounting remote filesystems."
    umount -a -tnfs &

    # you must have issued
    # 'cat /proc/mdstat | grep md0 > {your boot vol}/linux/raidgood.ref'
    # before linuxrc will execute properly with this info
    RAIDSTATUS=`/bin/cat /proc/mdstat | /usr/bin/grep md0 # capture raid status`

    # Turn off swap, then unmount local file systems.
    # clearing mdtab as well
    echo "Turning off swap."
    swapoff -a
    echo "Unmounting local file systems."
    umount -a -tnonfs

    # Don't remount UMSDOS root volumes:
    if [ ! "`mount | head -1 | cut -d ' ' -f 5`" = "umsdos" ]; then
      mount -n -o remount,ro /
    fi

    # root device remains mounted
    # mount dos file systems RW
    echo "Writing RAID read-only boot FLAG(s)."
    mount -n /dosa
    mount -n /dosc
    # create raid mounted RO flag in duplicate
    # containing the shutdown status of the raid array
    echo ${RAIDSTATUS} > /dosa/linux/raidstat.ro
    echo ${RAIDSTATUS} > /dosc/linux/raidstat.ro

    umount -n /dosa
    umount -n /dosc

    # Stop all the raid arrays (except root)
    echo "Stopping raid"
    mdstop -a

    # See if this is a powerfail situation.
    if [ -f /etc/power_is_failing ]; then
      echo "Turning off UPS, bye."
      /sbin/powerd -q
      exit 1
    fi

    # Now halt or reboot.
    echo "$message"
    [ ! -f /etc/fastboot ] && echo "On the next boot fsck will be FORCED."
    $command -f

