Root RAID HOWTO cookbook Michael A. Robinton, michael@bzs.org v1.13, July 17, 2000 This document only applys to the OLD raidtools, versions 0.50 and under. The workarounds and solutions addressed in this write up have largely been made obsolete by the vast improvment in the 0.90 raid­ tools and accompanying kernel patch to the 2.0.37, 2.2x and 2.3x series kernels. You may find the detailed descriptions useful, partic­ ularly if you plan to run root raid or use initrd. Check these links for a reference to set up of ``Boot Root Raid using conventional LILO'' and accompanying initrd working scripts. What follows is the description of the now OBSOLETE Root RAID HOWTO. This document was originally written to provide a cookbook for creating a root mounted raid filesystem and companion fallback rescue system using linux ini­ trd. There are complete step-by-step instruction for both raid1 and raid5 md0 devices. Each step is accompanied by an explanation of it's purpose. Included with this revision is a generic linuxrc initrd file which may be configured with a single three line ``/etc/raid­ boot.conf'' file for raid1 and raid5 configurations. ______________________________________________________________________ Table of Contents 1. Introduction 1.1 Where to get Up-to-date copies of this document. 1.2 More up-to-date Boot Root Raid with LILO howto 1.3 Bugs 1.4 Acknowledgements 1.5 Copyright Notice 2. What you need BEFORE YOU START 2.1 Required Packages 2.2 Other similar implementations. 2.3 Documentation -- Recommended Reading 2.4 RAID resources 3. Quick Start for ROOT RAID 4. (IT 4.1 Security Reminder 4.2 Build the Kernel and Raid Tools 4.3 Build the 4.4 Start the STEP by STEP instructions 4.5 Install the distribution - Slackware Specific 4.6 Install linux 4.7 Install Raid Tools 4.8 Remove un-needed directories and files from new filesystem. 4.9 Create /dev/md 4.10 Create a bare filesystem suitable for 4.10.1 Create the BOOT/RESCUE 4.10.2 Corrections for the Rescue System 4.11 Making 'initrd' boot the RAID device - linuxrc 4.12 Modifying the rc-scripts for SHUTDOWN 4.13 Configuring RAIDBOOT - raidboot.conf 4.14 Kernel 'loadlin and lilo' variables for RESCUE and RAID 5. Configuring the Production RAID system. 5.1 System specs. Two systems with identical motherboards were configured. 5.2 Partitioning the hard drives. 6. Building the RAID file system. 6.1 /etc/raid5.conf 6.2 /etc/raid1.conf 6.3 Step by Step procedures for building production RAID file system. 7. One last thought. 8. Appendix A. - Bohumil Chalupa's md0 shutdown 9. Appendix B. - Sample SHUTDOWN scripts 9.1 Slackware - /etc/rc.d/rc.6 9.2 Debian bo - /etc/init.d/halt and /etc/init.d/reboot 9.2.1 /etc/init.d/halt 9.2.2 /etc/init.d/reboot 10. Appendix C. - other setup files 10.1 linuxrc 10.2 loadlin -- linux.bat file - boot.par 10.3 linuxthreads Makefile.diff 10.4 raid1.conf 10.5 raid5.conf 10.6 raidboot.conf 10.7 rc.raidown 11. Appendix D. - obsolete linuxrc and shutdown scripts 11.1 Obsolete working - linuxrc 11.2 Obsolete working - shutdown scripts 12. Appendix E. - Gadi's raid stop patch for the linux kernel 13. Appendix F. - rc.raidown 14. Appendix G. - linuxrc theory of operation 15. Appendix H. Setting up ROOT RAID on RedHat ______________________________________________________________________ 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. Click here to browse the author's latest version of this document. Corrections and suggestions welcome! Root-RAID-HOWTO -- OBSOLETE Available in LaTeX (for DVI and PostScript), plain text, and HTML. http://www.linuxdoc.org/HOWTO/Root-RAID-HOWTO.html Available in SGML and HTML. ftp.bizsystems.net/pub/raid/ 1.2. More up-to-date Boot Root Raid with LILO howto Available in LaTeX (for DVI and PostScript), plain text, and HTML. http://www.linuxdoc.org/HOWTO/Boot+Root+Raid+LILO.html Available in SGML and HTML. ftp.bizsystems.net/pub/raid/ 1.3. 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. It takes over an hour on my 13 gig RAID5 array with a 20mb/sec scsi adaptor. 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!!! 1.4. 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 for the RAID howto that explained most of this to me. · Gadi Oxman for answering my dumb 'newbie' questions. · Ed Welbon for the execellent initrd.md package that inspired me to write this. · Bohumil Chalupa for implementing the re-boot 'workaround' that allows root-mounted-raid to work in a production environment. · Keith W. for his explaination of setting up root raid with RedHat. · and many others who contributed to this work in one way or another. 1.5. Copyright Notice This document is GNU copyleft by Michael Robinton 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-2.0.33 from sunsite · raid145-971022-2.0.31 patch adds support for raid1/4/5 · raidtools-pre3-0.42 tools to create and maintain raid devices (documentation too). · ``Gadi's raid stop patch'' in Appendix E. · linuxthreads-0.71 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 Helpful but not required · raidboot-0.01.tar.gz pre-built raid rescue/boot system. 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/ 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 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 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. You may also wish to review: · BootPrompt-HOWTO · man lilo · man lilo.conf 2.4. RAID resources · www.linas.org/linux/Software-RAID/Software-RAID.html · www.ssc.com/lg/issue17/raid.html · linas.org/linux/raid.html · ftp.kernel.org/pub/linux/daemons/raid/ · www.realtime.net/~welbon/initrd.md.tar.gz · luthien.nuclecu.unam.mx/~miguel/raid/ Mailing lists can be joined at: · majordomo@nuclecu.unam.mx send a message to subscribe raiddev send mail to: raiddev@nuclecu.unam.mx · majordomo@vger.rutgers.edu send a message to subscribe linux-raid send mail to: linux-raid@vger.rutgers.edu (this seems to be the most active list) 3. Quick Start for ROOT RAID If you use RedHat, see the ``Howto set up RedHat'' section in Appendix H. I have not tried this. If you use it successfully, please let me know so I can update this document. If you don't want to try and build and debug the rescue system, you can get a generic one created from Slackware-3.4 from: ftp.bizsystems.com/pub/raid/raidboot-0.01.tar.gz Perform the following steps: · Compile the raid enabled kernel with built in support for your disk subsystem · Test that the raid array will configure and mount correctly · Build your OS on the raid system · Correct the entries in fstab to show /dev/md0 as the root device. Make sure that the partition(s) you use for booting are included in fstab. · Modify your shutdown halt and reboot script(s) (mine is /etc/rc.d/rc.6) as shown in ``Modifying the rc-scripts for SHUTDOWN'' · Copy the following from you development filesystem to the rescue system AND the new raid system cd /root/raidboot mkdir mnt gzip -d rescue.clean losetup /dev/loop0 rescue.clean mount /dev/loop0 mnt copy these files cp -p /etc/* mnt/etc cp -p /etc/rc.d/* mnt/etc/rc.d {or as appropriate for your system} cp -a /lib/modules/* mnt/lib/modules Some Linux distributions include a test for the ro/rw status of the root file system. The rc startup files need to have this test removed for the initrd rescue system. See the instructions in the section on ``Correctons for Rescue System''. Correct the entries in fstab to show /dev/md0 as the root device. Make sure that the partition(s) you use for booting is included in fstab. Create /etc/raidboot.conf which describes the raid boot configuration. This file may NOT contain comments in the first three lines, after that it doesn't matter. raidboot.conf /dev/sda1 /dev/sda2 raidboot raid5.conf # comments may only be placed 'after' the three # configuration lines. # # This is '/etc/raidboot.conf' # # line one, the partition(s) containing the 'initrd' raid-rescue system # It is not necessary to boot from these partitions, however, # since the rescue system will not fit on floppy, it is necessary # to know which partitions are to be used to load the rescue system # # line two, the path to the raidboot config information # Where the shutdown status, etc... is located at boot time # It does NOT include the mount point information, only 'path' # /mntpoint/'path' # # line -3-, name of the raid configuration file # Current raid configuration file i.e. raid1.conf, raid5.conf A few more things to do and the raid systems is ready to boot. Create ``rc.raidown'', as described in Appendix F, and copy it to /etc/rc.d on the rescue, development, and raid system. Unmount the rescue system and zip it. umount mnt losetup -d /dev/loop0 mv rescue.clean rescue gzip rescue Copy the rescue file to the raidboot partitions. cp rescue.gz /mnt_point(1)/raidboot cp rescue.gz /mnt_point(2)/raidboot Activate the raid array. mdadd -ar Save the good reference status to the raidboot partition cat /proc/mdstat | grep md0 > /mnt_point(1)/raidboot/raidgood.ref cat /proc/mdstat | grep md0 > /mnt_point(1)/raidboot/raidgood.ref Lastly, configure the boot program as outlined in ``Boot Time Configu­ ration Parameters'' and reboot your system onto the raid array. 4. 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 RAID1 and RAID5 implementations. 4.1. 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!!! 4.2. 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. Make sure and include ``Gadi's raid stop patch'' in Appendix E. 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. 4.3. 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. I use loadlin to boot the kernel image and ramdisk from a dos partition simply because there are oddball devices in my system that have dos configuration software. Lilo will work just as well and a small linux partition can be used instead containing only the raid/boot files and the lilo record. For the raid boot/rescue system, 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, mdtab, raidX.conf, raidboot.conf /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. 4.4. 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 4.5. 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. 4.6. 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 4.7. 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 4.8. 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 4.9. Create /dev/md x 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 4.10. 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 4.10.1. 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 4.10.2. Corrections for the Rescue System Edit the following files to correct them for your rescue system. Some file names listed below are Slackware specific but have equivalents in other distributions. cd mnt Non-network etc/fstab 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 is read-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. These are the mountpoints for booting the system (boot partition and backup boot partition). My system boot from dos using loadlin, however linux partition(s) and lilo will work fine. My system uses: cd /root/raidboot/mnt <--- initrd root mkdir dosa dos partition mount point mkdir dosb 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! 4.11. 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. The theory of operation for this linuxrc file is discussed in ``Appendix G, linuxrc theory of operation''. A very simple and much easier to understand (working) linuxrc is included in ``Appendix D'', obsolete linuxrc and shutdown scripts. Copy the following text to linuxrc and save in your development area. -------------------- linuxrc ---------------------- #!/bin/sh # ver 1.13 3-6-98 # ################# BEGIN 'linuxrc' ################## # DEFINE FUNCTIONS # #################################################### # Define 'Fault' function in the event something # goes wrong during the execution of 'linuxrc' # FaultExit () { # correct fstab to show '/dev/ram0' for rescue system /bin/cat /etc/fstab | { while read Line do if [ -z "$( echo ${Line} | /usr/bin/grep md0 )" ]; then echo ${Line} else echo "/dev/ram0 / ext2 defaults 1 1" fi done } > /etc/tmp.$$ /bin/mv /etc/tmp.$$ /etc/fstab # point root at /dev/ram0 (the rescue system) echo 0x100>/proc/sys/kernel/real-root-dev /bin/umount /proc exit } # Define 'Warning' procdure to print banner on boot terminal # Warning () { echo '*********************************' echo -e " $*" echo '*********************************' } # Define 'SplitKernelArg' to help extract 'Raid' related kernel arguments SplitKernelArg () { eval $1='$( IFS=,; echo $2)' } #Define 'SplitConfArgs' to help extract system configuration arguments SplitConfArgs () { RaidBootType=$1 RaidBootDevice=$2 RaidConfigPath=$3 } ######################################################## ################### MAIN linuxrc ####################### ######################################################## # mount the proc file system /bin/mount /proc # Get the boot partition and configuration location from command line CMDLINE=`/bin/cat /proc/cmdline` for Parameter in $CMDLINE; do Parameter=$( IFS='='; echo ${Parameter} ) case $Parameter in Raid*) SplitKernelArg $Parameter;; esac done # check for 'required raid boot' if [ -z "${Raid_Conf}" ]; then Warning Kernel command line \'Raid_Conf\' missing FaultExit fi SplitConfArgs $Raid_Conf # tmp mount the boot partition /bin/mount -t ${RaidBootType} ${RaidBootDevice} /mnt # get etc files from primary raid system pushd /etc # this will un-tar into 'etc' (see rc.6) if [ ! -f /mnt/${RaidConfigPath}/raidboot.etc ]; then # bad news, this file should be here Warning required file \'raidboot.etc\' \ missing from ${RaidBootDevice}/${RaidConfigPath} \\n \ \\tUsing rescue system defaults else /bin/tar -xf /mnt/${RaidConfigPath}/raidboot.etc fi # get 'real' raidboot device for this boot # status path, and name of raidX.conf if [ ! -f /mnt/${RaidConfigPath}/raidboot.cfg ]; then # bad news, this file should be here Warning required file 'raidboot.cfg' \ missing from ${RaidBootDevice}/${RaidConfigPath}\\n \ \\tUsing rescue system defaults # Get the first raidX.conf file name in $RArg1 RaidBootDevs=$RaidBootDevice RaidStatusPath=$RaidConfigPath for RaidConfigEtc in $( ls raid*.conf ) do break; done else { read RaidBootDevs read RaidStatusPath read RaidConfigEtc } < /mnt/${RaidConfigPath}/raidboot.cfg fi popd /bin/umount /mnt # Set a flag in case the raid status file is not found # RAIDOWN="raidboot.ro not found" RAIDREF="raidgood.ref not found" echo "Reading md0 shutdown status." # search for raid shutdown status for Device in ${RaidBootDevs} do # these filesystem types should be in 'fstab' since # the partitions must be mounted for a clean raid shutdown /bin/mount ${Device} /mnt if [ -f /mnt/${RaidStatusPath}/raidboot.ro ]; then RAIDOWN=`/bin/cat /mnt/${RaidStatusPath}/raidboot.ro` RAIDREF=`/bin/cat /mnt/${RaidStatusPath}/raidgood.ref` /bin/umount /mnt break fi /bin/umount /mnt done # Test for a clean shutdown with array matching reference if [ "${RAIDOWN}" != "${RAIDREF}" ]; then Warning shutdown ERROR ${RAIDOWN} FaultExit fi # The raid array is clean, remove shutdown status files for Device in ${RaidBootDevs} do /bin/mount ${Device} /mnt /bin/rm -f /mnt/${RaidStatusPath}/raidboot.ro /bin/umount /mnt done # Write a clean superblock on all raid devices echo "write clean superblocks" /sbin/mkraid -f --only-superblock /etc/${RaidConfigEtc} # Activate raid array(s) if [ -z "$Raid_ALT" ]; then /sbin/mdadd -ar else /sbin/mdadd $Raid_ALT fi # If there are errors - BAIL OUT and leave rescue running if [ $? -ne 0 ]; then Warning some RAID device has errors FaultExit fi # Everything is fine, let the kernel mount /dev/md0 # tell the kernel to switch to /dev/md0 as the /root device # The 0x900 value is the device number calculated by: # 256*major_device_number + minor_device number echo "/dev/md0 mounted on root" echo 0x900>/proc/sys/kernel/real-root-dev # umount /proc to deallocate initrd device ram space /bin/umount /proc exit #------------------ end linuxrc ---------------------- Add 'linuxrc' to initrd boot device cd /root/raidboot chmod 777 linuxrc cp -p linuxrc mnt 4.12. 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 In debian 'bo' this is in both 'halt' and 'reboot' If you implement this in another distribution, please e-mail the instructions and sample files so they can be included here. 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 boot partitions are used to store the raidOK readonly status. I chose to write a file to each of the duplicate boot partitions 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 any of the hard drives die. The shutdown script is modified to call ``rc.raidown'' which saves the necessary information to successfully reboot and mount the raid device. Examples of shutdown scripts for various linux distributions are shown in ``Appendix B''. To capture the raid array shutdown status insert a call to ``rc.raidown'' after any case statements (if present) but before the actual shutdown (kills, status saves, etc...) begins and before the file systems are dismounted. ############ Save raid boot and status info ############## # if [ -x /etc/rc.d/rc.raidown ]; then /etc/rc.d/rc.raidown fi ################## end raid boot ######################### After all the file systems are dismounted (the root file system ################ for raid arrays ######################### # Stop all known raid arrays (except root which won't stop) if [ -x /sbin/mdstop ]; then echo "Stopping raid" /sbin/mdstop -a fi ########################################################## 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 boot partitions. All that remains is to creat the configuration file raidboot.conf and test the new file system by rebooting. 4.13. Configuring RAIDBOOT - raidboot.conf The comments following the example configuration file explain each of the three lines. This example file is for a 4 drive raid5 scsii array with duplicate boot partitions on drives sda1 and sdb1. Put the paramaters descriptive of your file systems here instead. /dev/sda1 /dev/sdb1 linux raid5.conf # comments may only be placed 'after' the three # configuration lines. # # This is 'raidboot.conf' # # line one, the partition(s) containing the 'initrd' raid-rescue system # It is not necessary to boot from these partitions, however, # since the rescue system will not fit on floppy, it is necessary # to know which partitions are to be used to load the rescue system # # line two, the path to the raidboot config information # Where the shutdown status, etc... is located at boot time # It does NOT include the mount point information, only 'path' # /mntpoint/'path' # # line -3-, name of the raid configuration file # Current raid configuration file i.e. raid1.conf, raid5.conf 4.14. Kernel 'loadlin and lilo' variables for RESCUE and RAID There are two kernel variables for the RESCUE and RAID system, only the first need be specified. · Raid_Conf=msdos,/dev/sda1,raidboot This variable points to raid boot device and configuration file. For floppy rescue boot, you may want to specify this on the kernel command line or in the loadlin or lilo boot file format: 'filesystem-type,device,path-to-config-from-mount­ point' · Raid_ALT=-r,-p5,/dev/md0,/dev/sda3 /dev/sdb3 /dev/sdc3 /dev/sdd3 Alternate mdadd parameters necessary when booting with non- redundant raid array. These are the comma separated command line parameters for mdadd. Unless they are needed to start a failed/non-redundant array, COMMENT OUT OR SPECIFY WITH A 'NULL'. i.e. Raid_ALT= Either of these parameters may be specified in the lilo or loadlin boot parameter file or on the loadlin kernel command line. Care must be taken that the maximum line length is not exceeded, however, if the command line is used (128 characters). When booting with lilo, the parameters are included in the lilo config file in the form: append="Raid_Conf=msdos,/dev/sda1,raidboot" append="Raid_ALT=-r,-p5,/dev/md0,/dev/sda3 /dev/sdb3 /dev/sdc3 /dev/sdd3" See man lilo.conf for more detailed information. Since I have some hardware that requires DOS configuration utilities, I have a small dos partition on the system. Therefore, I used loadlin to boot the raid5 system from the dos partition with a mirror (copy) on the companion disk. An identical method is used for the raid1 system. The example below uses loadlin, but the procedure is very similar for lilo. 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:\raidboot.bat c:\raidboot\loadlin.exe c:\raidboot\zimage c:\raidboot\rescue.gz c:\raidboot\raidboot.cfg c:\raidboot\raidboot.etc c:\raidboot\raidgood.ref c:\raidboot\raidstat.ro (only at shutdown) ---------------------- linux.bat --------------------------- echo "Start the LOADLIN process:" c:\raidboot\loadlin @c:\raidboot\boot.par -------------------- end linux.bat ------------------------- boot.par contains: # loadlin boot parameter file # # version 1.02 3-6-98 # linux kernel image c:\linux\zimage # target root device root=/dev/md0 #root=/dev/ram0 #root=/dev/sdc5 # mount root device as 'ro' ro # size of ram disk ramdisk_size=16384 # initrd file name initrd=c:\raidboot\rescue.gz #noinitrd # memory ends here mem=131072k # points to raid boot device, configuration file # for floppy rescue boot, you may want to specify # this on the command line instead of here # format 'filesystem-type,device,path-to-config-frm_mntpnt' Raid_Conf=msdos,/dev/sda1,raidboot # Alternate mdadd parameters # necessary when boot with non-redundant raid # otherwise, COMMENT OUT OR SPECIFY 'NULL' #Raid_ALT=-r,-p5,/dev/md0,/dev/sda3 /dev/sdb3 /dev/sdc3 /dev/sdd3 # ethernet devices ether=10,0x300,eth0 ***** >> 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. 5. Configuring the Production RAID system. 5.1. Two systems with identical motherboards were configured. System specs. Raid-1 Raid-5 Motherboard: Iwill P55TU dual ide adaptec scsi Processor: Intel P200 Disks: 2ea 7 gig 4 ea Segate 4.2 gig Maxtors wide scsii The disk drives are designated by linux as 'sda' through 'sdd' on the raid5 system and 'hda' and 'hdc' on the raid1 system. 5.2. Partitioning the hard drives. Since testing a large root mountable RAID array is difficult because of the ckraid re-boot problem, I re-partitioned my swap space to include a smaller RAID partition for testing purposes, sda6,sdb6,sdc6,sdd6, and a small root and /usr/src partition pair for developing and testing the raid kernel and tools. You may find this helpful. /dosx/raidboot/raidgood.ref shutdown -r now to do a clean reboot, and the system is up again. 6. Building the RAID file system. This description is for my RAID systems 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 6.1. /etc/raid5.conf # raid-5 configuration raiddev /dev/md0 raid-level 5 nr-raid-disks 4 chunk-size 32 # Parity placement algorithm parity-algorithm left-symmetric # Spare disks for hot reconstruction #nr-spare-disks 0 device /dev/sda3 raid-disk 0 device /dev/sdb3 raid-disk 1 device /dev/sdc3 raid-disk 2 device /dev/sdd3 raid-disk 3 6.2. /etc/raid1.conf # 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 6.3. Step by Step procedures for building production RAID file sys­ tem. For my RAID5 system I did a complete install of: Slackware-3.4 any current distribution should work OK linuxthreads-0.71 raidtools-0.42 linux-2.0.33 with raid145 patch and Gadi's patch Create and format the raid device. mkraid /etc/raid5.conf mdcreate raid5 /dev/md0 /dev/sda3 /dev/sdb3 /dev/sdc3 /dev/sdd3 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/raidboot/raidgood.ref cat /proc/mdstat | grep md0 > /dosb/raidboot/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 dosb 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 dosb cat /proc/mdstat | grep md0 > /dosa/raidboot/raidgood.ref cat /proc/mdstat | grep md0 > /dosb/raidboot/raidgood.ref mdstop /dev/md0 7. 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 for raid1 and once for raid5! Michael Robinton Michael@bzs.org 8. 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 > > 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 > 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 ----------------- 9. Appendix B. - Sample SHUTDOWN scripts · ``Slackware'' · ``Debian'' 9.1. Slackware - /etc/rc.d/rc.6 #! /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 # Modified by: Patrick J. Volkerding, # # Modified by: Michael A. Robinton < michael@bizsystems.com > # to add call to rc.raidown # 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 ############ Save raid boot and status info ############## # if [ -x /etc/rc.d/rc.raidown ]; then /etc/rc.d/rc.raidown fi ################## end raid boot ######################### # 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. $command -w # Save localtime [ -e /usr/lib/zoneinfo/localtime ] && cp /usr/lib/zoneinfo/localtime /etc # Asynchronously unmount any remote filesystems: echo "Unmounting remote filesystems." umount -a -tnfs & # Turn off swap, then unmount local file systems. echo "Turning off swap." swapoff -a echo "Unmounting local file systems." umount -a -tnonfs # Don't remount UMSDOS root volumes: if [ ! "`mount | head -1 | cut -d ' ' -f 5`" = "umsdos" ]; then mount -n -o remount,ro / fi ################ for raid arrays ######################### # Stop all known raid arrays (except root which won't stop) if [ -x /sbin/mdstop ]; then echo "Stopping raid" /sbin/mdstop -a fi ########################################################## # See if this is a powerfail situation. if [ -f /etc/powerstatus ]; then echo "Turning off UPS, bye." /sbin/powerd -q exit 1 fi # Now halt or reboot. echo "$message" [ ! -f /etc/fastboot ] && echo "On the next boot fsck will be FORCED." $command -f ############### end rc.6 ################################# 9.2. Debian bo - /etc/init.d/halt and /etc/init.d/reboot The modifications shown here for Debian bo halt and reboot files are NOT TESTED. When you test this, please e-mail me so I can remove this comment. 9.2.1. /etc/init.d/halt #! /bin/sh # # halt The commands in this script are executed as the last # step in runlevel 0, ie halt. # # Version: @(#)halt 1.10 26-Apr-1997 miquels@cistron.nl # PATH=/sbin:/bin:/usr/sbin:/usr/bin ############ Save raid boot and status info ############## # if [ -x /etc/rc.d/rc.raidown ]; then /etc/rc.d/rc.raidown fi ################## end raid boot ######################### # Kill all processes. echo -n "Sending all processes the TERM signal... " killall5 -15 echo "done." sleep 5 echo -n "Sending all processes the KILL signal... " killall5 -9 echo "done." # Write a reboot record to /var/log/wtmp. halt -w # Save the random seed between reboots. /etc/init.d/urandom stop echo -n "Deactivating swap... " swapoff -a echo "done." echo -n "Unmounting file systems... " umount -a echo "done." mount -n -o remount,ro / ################ for raid arrays ######################### # Stop all known raid arrays (except root which won't stop) if [ -x /sbin/mdstop ]; then echo "Stopping raid" /sbin/mdstop -a fi ########################################################## # See if we need to cut the power. if [ -x /etc/init.d/ups-monitor ] then /etc/init.d/ups-monitor poweroff fi halt -d -f ############# end halt #################### 9.2.2. /etc/init.d/reboot #! /bin/sh # # reboot The commands in this script are executed as the last # step in runlevel 6, ie reboot. # # Version: @(#)reboot 1.9 02-Feb-1997 miquels@cistron.nl # PATH=/sbin:/bin:/usr/sbin:/usr/bin ############ Save raid boot and status info ############## # if [ -x /etc/rc.d/rc.raidown ]; then /etc/rc.d/rc.raidown fi ################## end raid boot ######################### # Kill all processes. echo -n "Sending all processes the TERM signal... " killall5 -15 echo "done." sleep 5 echo -n "Sending all processes the KILL signal... " killall5 -9 echo "done." # Write a reboot record to /var/log/wtmp. halt -w # Save the random seed between reboots. /etc/init.d/urandom stop echo -n "Deactivating swap... " swapoff -a echo "done." echo -n "Unmounting file systems... " umount -a echo "done." mount -n -o remount,ro / ################ for raid arrays ######################### # Stop all known raid arrays (except root which won't stop) if [ -x /sbin/mdstop ]; then echo "Stopping raid" /sbin/mdstop -a fi ########################################################## echo -n "Rebooting... " reboot -d -f -i 10. Appendix C. - other setup files 10.1. linuxrc``linuxrc file'' 10.2. loadlin -- linux.bat file - boot.par``linux.bat file - boot.par'' 10.3. linuxthreads Makefile.diff``linuxthreads Makefile.diff'' 10.4. raid1.conf``raid1.conf'' 10.5. raid5.conf``raid5.conf'' 10.6. raidboot.conf``raidboot.conf'' 10.7. rc.raidown``rc.raidown'' 11. Appendix D. - obsolete linuxrc and shutdown scripts 11.1. Obsolete working - linuxrc This linuxrc file works fine with the shutdown procedure in the next subsection. ---------------------- linuxrc -------------------- #!/bin/sh # ver 1.07 2-12-98 # linuxrc - for raid1 using small dos partition and loadlin # # 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/raidboot/raidstat.ro ]; then RAIDOWN=`/bin/cat /dosa/raidboot/raidstat.ro` RAIDREF=`/bin/cat /dosc/raidboot/raidgood.ref` else if [ -f /dosc/raidboot/raidstat.ro ]; then RAIDOWN=`/bin/cat /dosc/raidboot/raidstat.ro` RAIDREF=`/bin/cat /dosc/raidboot/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/raidboot,etc... fi # The raid array is clean, proceed by removing # status file and writing a clean superblock /bin/rm /dosa/raidboot/raidstat.ro /bin/rm /dosc/raidboot/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 ---------------------- 11.2. Obsolete working - shutdown scripts This shutdown procedure works fine with the preceeding linuxrc 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/raidboot/raidstat.ro echo ${RAIDSTATUS} > /dosc/raidboot/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. The complete shutdown script from my old raid1 Slackware system follows, I have switched raid1 to the new procedure with the /etc/raidboot.conf 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 # Modified by: Patrick J. Volkerding, # Modified by: Michael A. Robinton, 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}/raidboot/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/raidboot/raidstat.ro echo ${RAIDSTATUS} > /dosc/raidboot/raidstat.ro umount -n /dosa umount -n /dosc # Stop all the raid arrays (except root) echo "Stopping raid" mdstop -a # See if this is a powerfail situation. if [ -f /etc/power_is_failing ]; then echo "Turning off UPS, bye." /sbin/powerd -q exit 1 fi # Now halt or reboot. echo "$message" [ ! -f /etc/fastboot ] && echo "On the next boot fsck will be FORCED." $command -f 12. Appendix E. - Gadi's raid stop patch for the linux kernel --- linux/drivers/block/md.c.old Fri Nov 21 13:37:11 1997 +++ linux/drivers/block/md.c Sat Dec 6 13:34:28 1997 @@ -622,8 +622,13 @@ return do_md_run (minor, (int) arg); case STOP_MD: - return do_md_stop (minor, inode); - + err = do_md_stop(minor, inode); + if (err) { + printk("md: enabling auto mdstop for %s\n", devname(inode->i_rdev)); + md_dev[minor].auto_mdstop = 1; + } + return err; + case BLKGETSIZE: /* Return device size */ if (!arg) return -EINVAL; err=verify_area (VERIFY_WRITE, (long *) arg, sizeof(long)); @@ -692,6 +697,10 @@ sync_dev (inode->i_rdev); md_dev[minor].busy--; + if (!md_dev[minor].busy && md_dev[minor].auto_mdstop) { + do_md_stop(minor, inode); + md_dev[minor].auto_mdstop = 0; + } } static int md_read (struct inode *inode, struct file *file, --- linux/include/linux/md.h~ Fri Nov 21 13:29:14 1997 +++ linux/include/linux/md.h Fri Nov 21 13:29:14 1997 @@ -260,6 +260,7 @@ int repartition; int busy; int nb_dev; + int auto_mdstop; void *private; }; 13. Appendix F. - rc.raidown Copy the following text into the script file rc.raidown and save it in /etc/rc.d. #! /bin/sh # # rc.raidown This file is executed by init when it goes into runlevel # 0 (halt) or runlevel 6 (reboot). It saves the status of # a root mounted raid array for subsequent re-boot # # Version: 1.08 3-25-98 Michael A. Robinton < michael@bizsystems.com > # ############ Save raid boot and status info ############## if [ -f /etc/raidboot.conf ] then { read RaidBootDevs read RaidStatusPath read RaidConfigEtc } < /etc/raidboot.conf # you must have issued # cat /proc/mdstat | grep md0 > # {your boot vol mnt(s)}/{RaidStatusPath}/raidgood.ref # before linuxrc will execute properly with this info # # capture raid status RAIDSTATUS=`/bin/cat /proc/mdstat | /usr/bin/grep md0` mkdir /tmp/raid$$ echo "Writing RAID read-only boot FLAG(s)." for Device in ${RaidBootDevs} do # get mount point for raid boot device or use tmp RBmount=$( cat /proc/mounts | /usr/bin/grep ${Device} ) if [ -n ${RBmounts} ]; then RBmount=$( echo ${RBmount} | cut -f 2 -d ' ' ) else RBmount="/tmp/raid$$" mount ${Device} ${RBmount} fi if [ -d ${RBmount}/${RaidStatusPath} ]; then # Create raid mounted RO flag = shutdown status of raid array echo ${RAIDSTATUS} > ${RBmount}/${RaidStatusPath}/raidboot.ro # Don't propagate 'fstab' from ramdisk if [ -f /linuxrc ]; then FSTAB= else FSTAB=fstab fi pushd /etc # Save etc files for rescue system /bin/tar --ignore-failed-read \ -cf ${RBmount}/${RaidStatusPath}/raidboot.etc \ raid*.conf mdtab* ${FSTAB} lilo.conf popd # Create new raidboot.cfg { /bin/echo ${RaidBootDevs} /bin/echo ${RaidStatusPath} /bin/echo ${RaidConfigEtc} } > ${RBmount}/${RaidStatusPath}/raidboot.cfg /bin/umount ${RBmount} fi done rmdir /tmp/raid$$ echo "Raid boot armed" fi ################## end raid boot ######################### 14. Appendix G. - linuxrc theory of operation This is the complex form of the linuxrc file for root mounted raid. It must be processed with 'bash' or another shell that recognizes shell functions. The advantage is that it is generic and is not dependent on startup files and parameters located in the initrd image. A Raid_Conf parameter passed to linuxrc by the kernel at boot from lilo or loadlin contains a pointer to the boot devices and location the of initial 2 raidboot files needed by linuxrc (raidboot.etc and raidboot.cfg placed by the shutdown script). raidboot.etc containing the 'tar'ed files: raid* mdtab* fstab lilo.conf ( if applicable ) from the primary system that are transferred to the initrd /etcetc directory at startup. With care, this file may be edited if necessary when your system 'really' crashes. raidboot.cfg contains the name of the boot partition in use and applicable backup(s) as well as the path to the rest of the raid start up file used by linuxrc. This file is normally created by the shutdown file and may be created manually if necessary. raidboot.cfg is of the form, 3 lines - no comments /dev/bootdev1 /dev/bootdev2 [/dev/bootdev3 ... and so on] raid-status/path name_of_raidX.conf_file the raid-status/path does not include the name of the mount­ point the raidX.conf filename is that one found in /etc and normally used for ckraid and mkraid. The following additional files reside on the permanent raid boot par­ titions. This is usually the same as above, but in emergency situa­ tions may be loaded from anywhere they are available, such as a floppy boot disk. · raidgood.ref created by the command cat /proc/mdstat | grep md0 > /{raid_status_path}/raidgood.ref See the ``shutdown scripts'' for saving this file and the next · raidstat.ro created at each shutdown by the shutdown rc file, saving the exit status of the raid array. 15. Appendix H. Setting up ROOT RAID on RedHat From the linux-raid@vger.rutgers.edu mail list. ! Has anyone figured out how to do root-mounted RAID (as per ! the Root-RAID HOWTO) using RedHat? The problem is that there ! is no equivalent of Slackware's setup to install the root ! filesystem to the RAID device. All RedHat installs have to ! run from the install floppy, which makes it almost ! impossible to get at the md devices and utilities during the ! install. ! ! I think it's much easier to go out of the distribution and do it by ! hand!! Assuming you have enough RAM (or a spare hard disk), install a minimal system onto what will be your swap space (or onto your spare hard disk) and/or /boot. Now do your mkraid, your mke2fs, mdrun, and mount. Next, do: tar clf - / | tar xpfC - /mnt/raidwasmountedhere (you may want a "v" in the second tar's flags) Once this is done, you can set up lilo (or whatever) so that the new raid partition is root. Then go in with RPM and/or glint (I hate glint's behavior in the face of failed dependencies, which was fixed but they broke it again for RH5.0 plus you can go back and forth forever between an old and a new version of a package without realizing the other version is installed) and install what you really wanted. All this assuming you couldn't sneak in at some point in the install and do your mkraid then at the VC with the shell prompt... ! I'm building a server at the moment and I think it would be tidier ! and less likely to cause problems in the future if I start with ! glibc2, rather than move to it later. ! ! Me too. ! ! The reason I'd like to be able to use RedHat is that they ! are the only major distribution that I know of with a ! glibc2-based release. ! ! Debian works fine with me. There isn't a CD yet, but you can grab the ! distribution by ftp. I avoided root-raid like the plague, largely because initrd is an extra, very fragile step (having to rdev, and having lilo depend on the bios' ID number to find the kernel's partition, are bad enough!). However, Red Hat does have a nice mkinitrd script, needed since they left all their SCSI drivers modular. Hack that to include your raid utils, make sure your mdadd -ar is in the right spot in /etc/rc.d/rc.sysinit (before any fscking) and make sure mdstop -a is in /etc/rc.d/init.d/halt after the RO-remount of /, and go for it! Keith kwrohrer@enteract.com