Re: iSCSI: revised error recovery hierarchy

[Santosh Rao <santoshr@cup.hp.com>]

> Arpakorn Boonkongchuen wrote:
> >
> > I have been following the iSCSI error recovery discussion
> > and have one question.  Is it a valid procedure for an
> > initiator who doesn't implement SNACK and does not want to
> > tear down the session and all connections when it gets a
> > data digest error to simply aborts the task (with task
> > management function request) associated with the bad
> > data digest received and tries to recover by resending the
> > command?
> >

Any initiator that does not implement SNACK will have to perform session
logout & re-login as the error recovery on digest errors that occurs on
the status PDU.

This is because of the current SNACK mechanism which will not allow the
initiator to acknowledge any further Status PDUs once a hole occurs in
the StatSN. The only way to workaround a hole in the StatSN sequence is
to either use a Status SNACK or to do a session logout.

So, its either SNACK support [and then choose your recovery level using
SNACK, command replay, command failover, etc.] or session recovery.

Something in between does'nt work. [at least not for long.]

Regards,
Santosh


>
> > It seems to me that this would fit between the level 0 and 1
> > as described in your slides.  Is this possible if you choose
> > level 1?  Please let me know if I miss something.
> >
> > regards,
> > Arpakorn
> >
begin:vcard 
n:Rao;Santosh 
tel;work:408-447-3751
x-mozilla-html:FALSE
org:Hewlett Packard, Cupertino.;SISL
adr:;;19420, Homestead Road, M\S 43LN,	;Cupertino.;CA.;95014.;USA.
version:2.1
email;internet:santoshr@cup.hp.com
title:Software Design Engineer
x-mozilla-cpt:;21088
fn:Santosh Rao
end:vcard