--wxIXENaY2CYUgF8u
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Sun, Feb 13, 2005 at 01:29:42PM -0500, Carl Alexander wrote:
> Is anyone working on ATA over ethernet support for NetBSD?=20
> The protocol is at http://www.coraid.com/documents/AoEr8.txt

I took a quick further look around the rest of this site.  It's one
vendor's cheap/cute hack, certainly aimed at the low end, but (as I've
noted elsewhere) that might fit in well for some uses.

In addition to the rfc-style protocol spec, there's also a protocol
design discussion document that is useful:
  http://www.coraid.com/documents/AoEDescription.pdf

=46rom this, and other things on the site, it seems that:

 - ordering is solved by having each request and response have tags,
   as i noted earlier.
 - they don't use jumbo frames on gig-e; although the protocol will
   accomodate that, their current implementation uses 100M ethernet per
   disk, and thus 2 sectors maximum data per command.
 - The host can queue/stream 'lots' of tagged messages (32 bit tag,
   not sure how many outstanding their disk server implementation
   allows) over the ethernet, and the server will asynchronously feed
   the physical ata interface from this queue.
 - they have a basic cooperative reservation style system for hosts to
   arbitrate ownership of disks

So, cheap and cheeful, and unashamedly pushing the compromise as far
as possible to one side. Surely the 1k per transaction is going to
impose some pretty strong per-disk speed limitations, and probably a
lot of host cpu overhead, but you could probably use it to build some
kinds of systems not well served by the compromise points in other
offerings.

For all that, the list prices on the website aren't nearly as low as
one might have hoped, though obviously they're in early low volume
stages.

--
Dan.

--wxIXENaY2CYUgF8u
Content-Type: application/pgp-signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.0 (NetBSD)

iD8DBQFCEbDMEAVxvV4N66cRAjfLAKDy4m58qI3squkk5UM6eB0KSR//HACg7Hso
IQx+3BMFjb+DiYRRKtbbb2I=
=5/Ph
-----END PGP SIGNATURE-----

--wxIXENaY2CYUgF8u--