Re: Integration of SCST in the mainstream Linux kernel

Nicholas A. Bellinger
2008-02-06T00:52:19Z

On Tue, 2008-02-05 at 16:48 -0800, Nicholas A. Bellinger wrote:
> On Tue, 2008-02-05 at 22:01 +0300, Vladislav Bolkhovitin wrote:
> > Jeff Garzik wrote:
> > > Alan Cox wrote:
> > >
> > >>>better. So for example, I personally suspect that ATA-over-ethernet is way
> > >>>better than some crazy SCSI-over-TCP crap, but I'm biased for simple and
> > >>>low-level, and against those crazy SCSI people to begin with.
> > >>
> > >>Current ATAoE isn't. It can't support NCQ. A variant that did NCQ and IP
> > >>would probably trash iSCSI for latency if nothing else.
> > >
> > >
> > > AoE is truly a thing of beauty. It has a two/three page RFC (say no more!).
> > >
> > > But quite so... AoE is limited to MTU size, which really hurts. Can't
> > > really do tagged queueing, etc.
> > >
> > >
> > > iSCSI is way, way too complicated.
> >
> > I fully agree. From one side, all that complexity is unavoidable for
> > case of multiple connections per session, but for the regular case of
> > one connection per session it must be a lot simpler.
> >
> > And now think about iSER, which brings iSCSI on the whole new complexity
> > level ;)
>
> Actually, the iSER protocol wire protocol itself is quite simple,
> because it builds on iSCSI and IPS fundamentals, and because traditional
> iSCSI's recovery logic for CRC failures (and hence alot of
> acknowledgement sequence PDUs that go missing, etc) and the RDMA
> Capable
> Protocol (RCaP).

this should be:

.. and instead the RDMA Capacle Protocol (RCaP) provides the 32-bit or
greater data integrity.

--nab