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• Adding a second SCSI adapter at boot on RHEL 4

  05Oct
  Author: ben Categories: Infrastructure Comments: 0

  At Applied Trust one of our servers has a built-in SCSI disk with a single LVM volume group and several logical volumes. It also has an Apple Xserve array attached via an LSI Logic fibre channel card. The Xserve array has a second volume group with only a single logical volume. The filesystems on all the logical volumes need to be mounted at boot for the system to work properly. Unfortunately, there seems to be some bug in RHEL4 that prevents the second volume group from being detected at boot unless the SCSI adapter module (mptscsih in this case) is inserted with initrd. The Red Hat installation did not support this configuration.

  To fix it, I added a second SCSI adapter to /etc/modprobe.conf:

  alias scsi_hostadapter1 mptscsih

  then I rebuilt initrd for the kernel we’re using:

  % sudo /sbin/mkinitrd ./initrd.img 2.6.9-5.ELsmp

  I inspected the new initrd manually to make sure the module would be loaded:

  % mkdir initrd
  % cp initrd.img initrd
  % cd !$
  % cd initrd
  % gunzip -S .img initrd.img
  % cpio -i < initrd
  cpio: dev/ram: Operation not permitted
  cpio: dev/console: Operation not permitted
  cpio: dev/tty3: Operation not permitted
  cpio: dev/null: Operation not permitted
  cpio: dev/tty1: Operation not permitted
  cpio: dev/tty4: Operation not permitted
  cpio: dev/systty: Operation not permitted
  cpio: dev/tty2: Operation not permitted
  4742 blocks
  % cat init
  #!/bin/nash
  
  mount -t proc /proc /proc
  setquiet
  echo Mounted /proc filesystem
  echo Mounting sysfs
  mount -t sysfs none /sys
  echo Creating /dev
  mount -o mode=0755 -t tmpfs none /dev
  mknod /dev/console c 5 1
  mknod /dev/null c 1 3
  mknod /dev/zero c 1 5
  mkdir /dev/pts
  mkdir /dev/shm
  echo Starting udev
  /sbin/udevstart
  echo -n "/sbin/hotplug" > /proc/sys/kernel/hotplug
  echo "Loading scsi_mod.ko module"
  insmod /lib/scsi_mod.ko
  echo "Loading sd_mod.ko module"
  insmod /lib/sd_mod.ko
  echo "Loading megaraid_mm.ko module"
  insmod /lib/megaraid_mm.ko
  echo "Loading megaraid_mbox.ko module"
  insmod /lib/megaraid_mbox.ko
  echo "Loading mptbase.ko module"
  insmod /lib/mptbase.ko
  echo "Loading mptscsih.ko module"
  insmod /lib/mptscsih.ko 
  echo "Loading dm-mod.ko module"
  insmod /lib/dm-mod.ko
  echo "Loading jbd.ko module"
  insmod /lib/jbd.ko
  echo "Loading ext3.ko module"
  insmod /lib/ext3.ko
  echo "Loading dm-mirror.ko module"
  insmod /lib/dm-mirror.ko
  echo "Loading dm-zero.ko module"
  insmod /lib/dm-zero.ko
  echo "Loading dm-snapshot.ko module"
  insmod /lib/dm-snapshot.ko
  /sbin/udevstart
  echo Making device-mapper control node
  mkdmnod
  echo Scanning logical volumes
  lvm vgscan --ignorelockingfailure
  echo Activating logical volumes
  lvm vgchange -ay --ignorelockingfailure VolGroup00
  echo Creating root device
  mkrootdev /dev/root
  umount /sys
  echo Mounting root filesystem
  mount -o defaults --ro -t ext3 /dev/root /sysroot
  mount -t tmpfs --bind /dev /sysroot/dev
  echo Switching to new root
  switchroot /sysroot
  umount /initrd/dev

  The bold section indicates that the mptscsih (and it’s dependency, mptbase) will be loaded by initrd.

  I moved the updated initrd to /boot:

  % sudo mv initrd.img /boot/initrd-2.6.9-5.ELsmp.atrust.img

  … then modified /boot/grub/grub.conf appropriately:

  # grub.conf generated by anaconda
  #
  # Note that you do not have to rerun grub after making changes to this file
  # NOTICE:  You have a /boot partition.  This means that
  #          all kernel and initrd paths are relative to /boot/, eg.
  #          root (hd0,0)
  #          kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00
  #          initrd /initrd-version.img
  #boot=/dev/sda
  default=0
  timeout=5
  splashimage=(hd0,0)/grub/splash.xpm.gz
  hiddenmenu
  title Red Hat Enterprise Linux WS Atrust (2.6.9-5.ELsmp)
          root (hd0,0)
          kernel /vmlinuz-2.6.9-5.ELsmp ro root=/dev/VolGroup00/LogVol00 rhgb quiet
          initrd /initrd-2.6.9-5.ELsmp.atrust.img
  title Red Hat Enterprise Linux WS (2.6.9-5.ELsmp)
          root (hd0,0)
          kernel /vmlinuz-2.6.9-5.ELsmp ro root=/dev/VolGroup00/LogVol00 rhgb quiet
          initrd /initrd-2.6.9-5.ELsmp.img
  title Red Hat Enterprise Linux WS-up (2.6.9-5.EL)
          root (hd0,0)
          kernel /vmlinuz-2.6.9-5.EL ro root=/dev/VolGroup00/LogVol00 rhgb quiet
          initrd /initrd-2.6.9-5.EL.img

  Reboot for settings to take effect.

  
  Tags: linux