Re: iSCSI: remove recovery from transport-layer connection failure(?)

[Mark Bakke <mark.bakke@nuspeed.com>]

I agree with John that we should keep it.  We had put it in so we
could recover from lost connections for any SCSI device.  Without
this mechanism, the only device that would be recoverable is disk.

BTW, NDMP is a file-level protocol; it is used by backup products
to instruct a file server to write certain files to tape.  We
still need to be able to write tape at the block level, either
directly or via a third-party copy.

Even if we end up with a single connection per session, we will
still have to acknowledge receipt of status to the target, and
be able to recover sessions if the TCP stream is lost for some
reason.

--
Mark


John Hufferd/San Jose/IBM wrote:
> 
> Costa,
> This is not a replacement for Tape.  Tape is used for other things besides
> Backup.  Also, NDMP is a Client/Server  protocol.  Someone still needs to
> talk to the tape with SCSI or FC.  The actual tape needs to be locatable
> anywhere. This is still the need for iSCSI.
> 
> .
> .
> .
> John L. Hufferd
> 
> csapuntz@csapuntz-u1.cisco.com@ece.cmu.edu on 09/22/2000 02:15:06 PM
> 
> Sent by:  owner-ips@ece.cmu.edu
> 
> To:   ips@ece.cmu.edu
> cc:
> Subject:  iSCSI: remove recovery from transport-layer connection failure(?)
> 
> Currently, iSCSI is spec'ed to recover from transport-layer
> connection failures.
> 
> The main motivation for this decision was to support tape backup
> applications that are quite sensitive to any failures that get
> propogated to their layer.
> 
> However, there are other ways of doing backup over IP than
> SCSI/iSCSI.  NDMP (www.ndmp.org) and devices that implement it are
> already shipping.
> 
> So, perhaps we can remove the requirement of recovering from
> transport-layer connection failures in iSCSI. This would simplify
> the protocol somewhat.
> 
> Thoughts?
> 
> -Costa

-- 
Mark A. Bakke
NuSpeed, Inc.
mark.bakke@nuspeed.com
763.398.1054