Subject: Re: iSCSI - Recovery Levels

From: "John Hufferd" <[email-masked]>
Date: Mon, 3 Sep 2001 12:14:10 -0700

Julian,
The way you have written it, only two levels can be specified, since level
one contains all the currently know levels.  Perhaps, you need to leave
some space between Zero and Everything currently known, by assigning
Everything to be number 2, or, 3 etc.  If we define it to be the number 2
for instance then it is possible that we only define 0 and 2 but it would
leave room for a 1 if one was defined.

.
.
.
John L. Hufferd
Senior Technical Staff Member (STSM)
IBM/SSG San Jose Ca
Main Office (408) 256-0403, Tie: 276-0403,  eFax: (408) 904-4688
Home Office (408) 997-6136
Internet address: [email-masked]

Julian Satran/Haifa/IBM@[email-masked] on 09/03/2001 06:59:38 AM

Sent by:  [email-masked]

To:   [email-masked]
cc:
Subject:  iSCSI - Recovery Levels

There seems to be consensus around the fact the recovery leves are good and
no
clear consensus about hpow many should there be (2 or 3).

As there is no chance to settle this until 08 gets out I suggest
intrdocucing
a generic key=value pair (RecoveryLevel) and remove the existing keys
(CommmandFailoverSupport and CommandReplaySupport).

RecoveryLevel will be defined as follows:

01   RecoveryLevel

   Use: LO
   Who can send: Initiator and Target

   RecoveryLevel=<0 to x>

   Default is 0.

   Initiator and target negotiate the recovery level supported.
   The minimum of the two values is selected.

   Recovery levels represent a combination of recovery capabilities.
   Each recovery level includes all the capabilities of the lower recovery
   levels and adds to them some new ones.

   In the recovery mechanisms descriptions some specific recovery
   capabilities are used.

   Those are mapped to levels as follows:

      0 - SessionRecovery
      1 - CommandFailoverSupport and CommandReplaySupport
      [TBD]

 Comments?

 Julo

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From: "Sanjeev Bhagat \(TRIPACE/Zoetermeer\)" <[email-masked]>
Date: Mon, 3 Sep 2001 22:08:33 +0200

Or, it might still be better if some x (eg. 7) value is kept and anything
between 0 and x is reserved. 0 means no recovery and 7 means full recovery.
Once we go thoroughly into dividing the recovery level then the various
reserved values can be defined.

Sanjeev