Re: iSCSI: Recovery R2T

["Mallikarjun C." <cbm@rose.hp.com>]

Michael,

You're referring to a different, but related issue now.  We had debated
your new issue in the past, look at the last para in section 11.20.  
--
Mallikarjun

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions
Hewlett-Packard MS 5668 
Roseville CA 95747
cbm@rose.hp.com


----- Original Message ----- 
From: "Michael Morrison" <mmorrison@istor.com>
To: <cbm@rose.hp.com>
Cc: "iSCSI" <ips@ece.cmu.edu>
Sent: Friday, July 12, 2002 10:43 AM
Subject: Re: iSCSI: Recovery R2T


> Mallikarjun,
> 
> Your definition looks OK to me.  But I'm concerned about the case of
> DataSequenceInOrder
> being set to Yes.  The R2T text allows the target to send a recovery
> R2T, but the
> text in 11.20 says that the initiator cannot send the requested data as
> it's not a continuously non-decreasing offset.  
> 
> >From 9.8 (R2T)
>  DataSequenceInOrder governs the buffer offset ordering in consecu-
>    tive R2Ts. If DataSequenceInOrder is Yes, then consecutive R2Ts
>    SHOULD refer to continuous non-overlapping ranges.
> 
> >From 11.20
> If DataSequenceInOrder is set to Yes, Data Sequences MUST be trans-
>    ferred using continuously non-decreasing sequence offsets (R2T buffer
>    offset for writes, or the smallest SCSI Data-In buffer offset within
>    a read data sequence).
> 
> Mike
> 
> On Fri, 2002-07-12 at 10:31, Mallikarjun C. wrote:
> 
>     Michael,
>     
>     It appears to me that we need to define the term `recovery R2T' - 
>     the lack of which David Black also pointed out earlier.
>     
>     Here's what I propose we should define it as:
>     
>     Recovery R2T: It is an R2T generated by a target upon detecting 
>     the loss of one or more Data-Out PDUs through one of the following means
>     - a digest error, a sequence error, or a sequence timeout.  A recovery
>     R2T carries the next unused R2TSN, but requests part of or the entire
>     data 
>     burst that an earlier R2T (with a lower R2TSN) had already requested.
>     
>     I believe the MUST/SHOULD/MAY language contained in Section 6 already 
>     defines the expectations on the usage scope of recovery R2T.
>     -- 
>     Mallikarjun 
>     
>     
>     Mallikarjun Chadalapaka
>     Networked Storage Architecture
>     Network Storage Solutions
>     MS 5668 Hewlett-Packard, Roseville.
>     cbm@rose.hp.com
>     
>     
>     > Michael Morrison wrote:
>     > 
>     > 
>     > 
>     > If an initiator sends multiple Data-Out in response to an R2T, and one
>     > of the Data-Out in the
>     > sequence has a data digest error, can the recovery R2T solicit only
>     > the missing data, or must
>     > it solicit the whole sequence?   I can't find anything in the draft
>     > that defines what the contents
>     > of a recovery R2T MUST/SHOULD/MAY contain.
>     > 
>     > Thanks
>     > Michael Morrison
>     > ISTOR Networks
>     > 7585 Irvine Center Dr. Ste 250
>     > Irvine Ca. 92618
>     > PGP Key: 74C30155
> 
> Michael Morrison
> ISTOR Networks
> 7585 Irvine Center Dr. Ste 250
> Irvine Ca. 92618
> PGP Key: 74C30155
> 
>