[syslinux] hello and aoe booting

[Gene Cumm]

On Tue, Feb 3, 2009 at 5:31 AM, Jean Spirat <jeanspirat at squirk.org> wrote:
> hi to the list,
>
>  Hello everyone, I am new in the world of pxe booting and i try to use
> AOE to boot my linux debian lenny machines.

Cool.  Researching your issue has made me examine how AoE works and
how to use it.

> i install a system on the partition i created (using FAI/debootstrap).
> Then i try to boot, i use sanboot.c32 (as it seems the thing to use):
>
> - in  dhcpd.conf:
>
>   filename     "gpxelinux.0";
>
> - in the /pxelinux.cfg/default
>
>        kernel http://10.1.0.251/kernel/sanboot.c32
>        append aoe:e10.1
>
> (i also tried e10.1px), but it fails with this error:
>
> AoE booting from aoe:e10.1
> Could not initialise AoE device: Connection timed out (0x4c006035)
> C uld not boot from aoe:e10.1: Connection timed out (0x4c006035)
> SAN boot failed.
>
> i have 4 ethernet card on this machine 1 front, 1 back and 2 AOE

What is the full layout of your network?  Are the AoE cards dedicated
AoE cards like the Coraid EtherDrive HBAs?  Are your AoE targets only
visible from the AoE cards?  Are the DHCP and PXE servers only visible
from one of the non-AoE interfaces?

> Is there any way to debug and see what sanboot is doing  to have a
> better idea of what is failing ?

Use another machine with packet sniffing tools like wireshark with all
three connected either to a hub or to a managed switch with something
like port mirroring enabled in order to watch the traffic across the
AoE cards or across the regular cards.

For a working example, I just built a simple AoE test setup.  I used a
host-based VM system with two configured VMs.  The host runs a DHCP
server and TFTP server configured to load gpxelinux for PXE clients
(including the quick test of the gPXE CD).  On one VM, I configured a
simple disk to demonstrate booting and read/write I/O.  I then used
the SLAX AoE LiveCD to provide a quick AoE target from that simple
disk.  In the second VM, I tested both regular PXE booting and using
the gPXE CD to load gPXELINUX and then use sanboot.c32 to attach to
the AoE target.

>From this demonstration, my best guess is that gPXE produces a
BIOS-level software interface to an AoE device by altering the normal
hard drive interface.  Testing several things resulted in seeing what
was originally the first hard drive remapped to a different location
depending on the exact IDE configuration.

Based on this, if the two AoE cards are dedicated cards with a BIOS
extension available (like you would see with many SCSI cards and boot
capable NICs), I'd think that using the AoE BIOS would be an easier
route than attempting to use a network boot.

-Gene

"No one ever says, 'I can't read that ASCII E-mail you sent me.'"