Re: [Qemu-devel] XP install cores with SCSI LSI 53C895A disks

[Michael Tokarev]

On 08.03.2012 11:44, Gerd Hoffmann wrote:
> On 03/07/12 20:58, Gerhard Wiesinger wrote:
>> On Wed, 7 Mar 2012, Brian Jackson wrote:
>>> I think most people trying to use qemu for anything useful have given
>>> up on if=scsi. Some distros even disable support because they don't
>>> want to QA it. That should be a decent sign that you may want to avoid
>>> it.
>>
>> OK, but SAS (Serial attached SCSI) is technology in the area of storage
>> interface technology where all big storage vendors see future (e.g. they
>> give up: FC and SATA drives, SATA drives are replaced by MDL SATA drives
>> (SATA 7200RPM drives with SAS interface)).
> 
> The problem isn't scsi.  The problem is the lsi adapter.  Problem #1 is
> the hardware design which makes it hard to emulate it correctly and #2
> that you need a non-redistributable rom file to boot from it.

#2 isn't an issue actually, at least for Debian users --
I just patched extbook back to allow booting from scsi and
to let people some transition time to move from boot=on
syntax which was supported before 1.0 and dropped suddenly
without any warnings in 1.0, breaking people setup.  I
think I'll continue shipping extboot support at least as
long as there's no native support for scsi booting in bios.

/mjt

>> Therefore I don't understand why distros are giving up SAS which is also
>> SCSI (of course old legacy SCSI is understandable).
> 
> Nobody gives up on scsi.  See virtio-scsi merged recently.  There also
> is megasas aiming for merge (which shares the boot issue with lsi though).
>