[Stgt-devel] [ofa-general] Re: [Ips] Calculating the VA in iSER header

Eli Dorfman dorfman.eli
Thu Apr 17 13:13:01 CEST 2008

On Wed, Apr 16, 2008 at 6:46 PM, Roland Dreier <rdreier at cisco.com> wrote:
>  > Agree with the interpretation of the spec, and it's probably a bit
>   > clearer that way too.  But we have working initiators and targets
>   > that do it the "wrong" way.
>  Yes... I guess the key question is whether there are any initiators that
>  do things the "right" way.
>   > 1. Flag day: all initiators and targets change at the same time.
>   > Will see data corruption if someone unluckily runs one or the other
>   > using old non-fixed code.
>  Seems unacceptable to me... it doesn't make sense at all to break every
>  setup in the world just to be "right" according to the spec.

This will break only when both initiator and target will use
InitialR2T=No, which means allow unsolicited data.
As far as I know, STGT is not very common (and its version in RHEL5.1
is considered experimental). Its default is also InitialR2T=Yes.
Voltaire's iSCSI over iSER target also uses default InitialR2T=Yes.
So it seems that nothing will break.

>   > 2. Rewrite the IB Annex to codify what's done in practice, and don't
>   > "fix" any code.
>  If existing practice is universally to do things "wrong" then this seems
>  to me by far the best way to proceed.

Assuming there aren't many iSER installation that currently work with
unsolicited data, then it is the right time to do it right.
Future implementation will rely on the spec and unless you modify the
spec this will lead to greater confusion.

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