Differences between revisions 26 and 27
Revision 26 as of 2008-08-26 16:49:12
Size: 3404
Comment: add reference to grub legacy package
Revision 27 as of 2009-01-30 10:57:19
Size: 3566
Comment: grub update
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== D-I Multipath Testing ==
  
To enable multipath support during installation use
{{{
    install disk-detect/multipath/enable=true
}}}
at the installer prompt. If multipath devices are found these will show up as ''/dev/mapper/mpath<X>'' during installation.

=== Installing Grub Legacy ===
Since neither Debian's ''grub'' nor ''grub2'' support multipath device names yet ([http://bugs.debian.org/483971 483971]), you have to manually install a [http://bugs.debian.org/442382 patched] ''grub'' legacy during installation. A prebuilt deb for i386 is available [http://honk.sigxcpu.org/projects/multipath-tools/lenny here]. (In case you need to built for another architecture, the sources are available via [http://git.debian.org/?p=users/agx/grub-legacy.git this git tree]).

In order to install the patched grub finish the installation until you're asked to reboot. Then:

 * spawn a shell in d-i.
 * copy the patched grub deb to ''/target/tmp''.
 * then do:
{{{
  chroot /target
  dpkg -i /tmp/grub*deb
  echo "(hd0) /dev/mapper/mpath0" > /boot/grub/device.map
  grub --device-map=/boot/grub/device.map
}}}
 * assuming your root filesystem is the first partition on the first multipath device (''/dev/mapper/mpath0-part1'') enter at the grub prompt:
{{{
  root (hd0,0)
  setup (hd0)
  quit
}}}
 * this should complete without errors
 * close the shell (''CTRL-D'')
 * reboot the system
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This needs to be done to support [http://sources.redhat.com/lvm2/wiki/MultipathUsageGuide multipath]ing natively in DebianInstaller: This needed/needs to be done to support [http://sources.redhat.com/lvm2/wiki/MultipathUsageGuide multipath]ing natively in DebianInstaller:
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 * hw-detect: disk-detect.sh needs to pull in /sbin/multipath and the necessary kernel modules. If there are multipathed devices we need to also pull in partman-multipath. ([http://bugs.debian.org/440439 #440439]) - '''done'''
 * parted: correctly identify multipathed devices ([http://bugs.debian.org/440675 #440675]) - '''done'''
 * hw-detect: disk-detect.sh needs to pull in /sbin/multipath and the necessary kernel modules. If there are multipath devices we need to also pull in partman-multipath. ([http://bugs.debian.org/440439 #440439]) - '''done'''
 * parted: correctly identify multipath devices ([http://bugs.debian.org/440675 #440675]) - '''done'''
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  * needs to skip block devices that are part of a multipathed device (part_of_multipath())   * needs to skip block devices that are part of a multipath device (part_of_multipath())
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 * put up a [http://honk.sigxcpu.org/projects/multipath-tools/d-i/ netboot image] for easy testing

All the points above do have patches attached, you'll need all the ones that aren't already marked as '''done''' to get working multipath support in d-i.

== Multipath Testing ==
  
To enable multipath support during installation use
{{{
    install disk-detect/multipath/enable=true
}}}
at the installer prompt. If multipathed devices are found these then show up as ''/dev/mapper/mpathX'' during installation.

=== Installing Grub Legacy ===
As mentioned above since ''grub2'' doesn't support multipath yet ([http://bugs.debian.org/483971 483971]), you have to install a [http://bugs.debian.org/442382 patched] ''grub'' legacy in the newly installed system. A prebuilt deb is available [http://honk.sigxcpu.org/projects/multipath-tools/lenny here] ([http://git.debian.org/?p=users/agx/grub-legacy.git git tree]).

Finish the installation until you're asked to reboot. Then:

 * spawn a shell in d-i.
 * copy the patched grub deb to ''/target/tmp''
 * then do:
{{{
  chroot /target
  dpkg -i /tmp/grub*deb
  echo "(hd0) /dev/mapper/mpath0" > /boot/grub/device.map
  grub --device-map=/boot/grub/device.map
}}}
 * assuming your rootfs is on ''/dev/mapper/mpath0-part1'' enter at the grub prompt:
{{{
  root (hd0,0)
  setup (hd0)
}}}
 * done - you can now reboot
 * put up a for easy testing - '''done''' - you can use the [http://www.debian.org/devel/debian-installer/ official Lenny RC images]

/!\ In order to test Multipath in d-i you still need a patched grub ([http://bugs.debian.org/442382 #442382]) but see below.

D-I Multipath Testing

To enable multipath support during installation use

    install disk-detect/multipath/enable=true

at the installer prompt. If multipath devices are found these will show up as /dev/mapper/mpath<X> during installation.

Installing Grub Legacy

Since neither Debian's grub nor grub2 support multipath device names yet ([http://bugs.debian.org/483971 483971]), you have to manually install a [http://bugs.debian.org/442382 patched] grub legacy during installation. A prebuilt deb for i386 is available [http://honk.sigxcpu.org/projects/multipath-tools/lenny here]. (In case you need to built for another architecture, the sources are available via [http://git.debian.org/?p=users/agx/grub-legacy.git this git tree]).

In order to install the patched grub finish the installation until you're asked to reboot. Then:

  • spawn a shell in d-i.
  • copy the patched grub deb to /target/tmp.

  • then do:

  chroot /target
  dpkg -i /tmp/grub*deb
  echo "(hd0) /dev/mapper/mpath0" > /boot/grub/device.map
  grub --device-map=/boot/grub/device.map
  • assuming your root filesystem is the first partition on the first multipath device (/dev/mapper/mpath0-part1) enter at the grub prompt:

  root (hd0,0)
  setup (hd0)
  quit
  • this should complete without errors
  • close the shell (CTRL-D)

  • reboot the system

Multipath Support in Debian Installer:

This needed/needs to be done to support [http://sources.redhat.com/lvm2/wiki/MultipathUsageGuide multipath]ing natively in DebianInstaller: