Boot method: DVD from external DVD reader with USB connection
Image version: http://cdimage.debian.org/cdimage/squeeze_di_rc1/amd64/iso-cd/debian-sq-di-rc1-amd64-netinst.iso
Date: 17 January 2011

Machine: DELL OptiPlex 780 SF
Processor: Intel E7500
Memory: 2Gb
Partitions:

Output of lspci -knn (or lspci -nn):

Base System Installation Checklist:
[O] = OK, [E] = Error (please elaborate below), [ ] = didn't try it

Initial boot:           [O]
Detect network card:    [O]
Configure network:      [O]
Detect CD:              [ ]
Load installer modules: [O]
Detect hard drives:     [O]
Partition hard drives:  [O]
Install base system:    [O]
Clock/timezone setup:   [O]
User/password setup:    [O]
Install tasks:          [O]
Install boot loader:    [E]
Overall install:        [E]

Comments/Problems:

this machine have two sata disks connected to a intel software raid
controller. The two disks have been connfigured as one logical disk in
mirror using the controller BIOS.

The linux install has been started with "dmraid=true" option and the
logical disk has been correctly detected and configured.

When the bootloaded has to be installed, grub-pc was selected and
proposed to install itself on mbr since no other OSes were detected. I
pressed OK and the grub installation failed with a message like 'cannot
setup grub on /dev/sda'. This is correct since /dev/sda should not be
used because it is part of the /dev/mapper/isw_XXXXXXX_ARRAY.

Reading the documentation I found that grub2 does not support this kind
of raid controller, nor lilo does. So, it seems Debian cannot be
installed at all on such system.

Bye,
Giuseppe

Correct.  dmraid is not supported (it's experimental).

However, mdraid supports intel raid now it seems, so perhaps it you try
that it will work.

grub2 does have the current question of how to tell if an md raid is
pure software, or intel fake raid.  Not sure that has been resolved yet.

Correct.  dmraid is not supported (it's experimental).

However, mdraid supports intel raid now it seems, so perhaps it you try
that it will work.

grub2 does have the current question of how to tell if an md raid is
pure software, or intel fake raid.  Not sure that has been resolved yet.

Il giorno lun, 17/01/2011 alle 17.28 -0500, Lennart Sorensen ha scritto:
[...]

Do you mean that removing logical volume on ISW and creating an MD
mirror (i.e., software mirror via normal kernel modules) I would get a
software mirror accelerated with ISW hardware?

Bye,
Giuseppe

Il giorno lun, 17/01/2011 alle 17.28 -0500, Lennart Sorensen ha scritto:
[...]

Do you mean that removing logical volume on ISW and creating an MD
mirror (i.e., software mirror via normal kernel modules) I would get a
software mirror accelerated with ISW hardware?

Bye,
Giuseppe

There is no hardware acceleration as this is a fake raid controller.
The only reason to use it instead of mdadm software raid is if you
must dual boot with Windows.  If you don't do that, then mdadm is much
better supported and feature complete.

For what it's worth, you can choose to install grub to the /dev/mapper
device and it works in Ubuntu.  I'm not sure if we're carrying patches
that are needed off the top of my head.