Re: [Xen-users] HVM iSCSI Boot ROM

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Tue, Aug 05, 2008 at 02:09:52PM -0600, Nick Couchman wrote:
> Microsoft has their "boot" version of their iSCSI software initiator.  
> Apparently this still requires that the network card be iSCSI Boot "enabled." 
>  
> Intel seems to be the only obvious company out there supporting it on their 
> Server adapters - I was wondering if there are any thoughts/plans on 
> implementing 
> iSCSI Boot functionality in the HVM Boot ROM?  Or maybe there's already 
> some way to do it, with something like etherboot? 
> 

I think broadcom server NICs support iSCSI boot too.

broadcom+dell:
http://www.dell.com/downloads/global/power/ps4q07-20070596-Broadcom.pdf

press releases:
http://www.embeddedstar.com/press/content/2004/10/embedded16905.html
http://www.linuxelectrons.com/news/hardware/14128/broadcoms-iscsi-block-storage-over-ethernet-delivers-high-performance
http://www.broadcom.com/press/release.php?id=635611
http://www.byteandswitch.com/document.asp?doc_id=61762
http://news.thomasnet.com/companystory/810702


also, IBM blades contain iBFT capable iSCSI initiator in their BIOS, allowing
iSCSI boot without HBA. 


Some links about booting from iSCSI disk without iSCSI HBA (using just the
normal NIC and iBFT table):

http://etherboot.org
http://etherboot.org/wiki/sanboot
http://www.etherboot.org/wiki/iscsiboot
http://www.etherboot.org/wiki/ibft

Although I'm not sure how up-to-date those pages are.. 

Anyway, the basic idea for iSCSI boot nowadays is that the iSCSI boot
initiator (BIOS, NIC or firmware) doing the initial boot up (loading GRUB 
from the disk, int13h emulation) should fill up iBFT table with iSCSI NIC/IP 
configuration info, and also the target/LUN info. 

The booted OS can then set up it's iscsi software initiator based on the 
info in iBFT table. iBFT table is stored in memory.  

RHEL 5.2 (and CentOS 5.2) already supports this. Microsoft iSCSI software
initiator (boot version) also supports iBFT, I think.

So yeah.. to support iSCSI boot for HVM guests would mean being able to specify
iBFT information in the domain configuration, and that information should
end up in iBFT table in HVM domain memory. And then there should be int13h
emulation using that same iBFT information so that bootloaders (GRUB) work.. 

Shouldn't be that hard thing to implement :) 

-- Pasi

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