Re: Linux as a SCSI _Target_ device?

Bob McElrath (mcelrath@draal.physics.wisc.edu)
Wed, 11 Nov 1998 22:35:40 -0600 (EST)


On Wed, 11 Nov 1998, MOLNAR Ingo wrote:

> On Tue, 10 Nov 1998, Jeff Noxon wrote:
>
> > Can anyone tell me if it would be possible to make a Linux system appear
> > to another system as a SCSI target? I want to RAID 5 a whole mess of
> > IDE drives and have it appear to another Linux box as a SCSI hard drive.
> > I'm guessing it would be possible with one of the Symbios chips and some
> > clever hacking. True/False? Where to start?
> >
> > If I need special hardware, I'm out.
>
> i'm not sure wether such a thing exists in retail, but you also need
> kernel support for this. The point would be to 'export' a block device
> (RAID5) as an SCSI target.
>
> i was thinking about this one yes, this way Linux could be a real
> hardware-RAID box. It's _not_ really complex, but i havent seen this yet.
> The board has to do something like this:
>
> - send an IRQ if an SCSI command arrives
> - should be able to DMA out to the SCSI bus and also accept DMA
> transfers.
>
> probably there are some RT considerations (Linux has to react within a
> given timeframe), but maybe not, and Linux can sure can do much better
> than the millisec-timescale of RAID arrays. It is an interesting project.
> True 50-500G hardware-RAID for $5K or so.

You might also be interested in the work people have done on encapsulating
IP in SCSI (which also requires Linux to act as a SCSI target). Here's one
URL I found:
http://shoga.wwa.com/~scottr/sd/design/index.htm

good luck!
-- Bob

./'^`\._./'~`\._./'~`\._./'~`\._./'#`\._./'~`\._./'~`\._./'~`\._./'^`\.
/ Rube Goldberg? Bah! Amateur! I give you..Windows 98! Linux everywhere \
| Linux, because everyone's work is mission critical. ANYTHING inside. |
|_Bob McElrath (mcelrath@wisconsin.cern.ch) Univ. of Wisconsin at Madison_|
\.___________________________________________________________________./

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