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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: iSCSI:Clear Task SetJohn, That looks more like in T10 territory. T10 defines differently Abort Task Set and Clear Task Set. We could either: decide not to implement clear task set (T10 allows that but "per target" not "per transport") enable clear task set - in which case we have to say something about the relative order of the task management request with regard to the task comming from other initiators - and that is what I attempted to say in 9.4 Julo John Hufferd/San Jose/IBM@IBMUS Sent by: owner-ips@ece.cmu.edu 23-11-01 23:30 To: Julian Satran/Haifa/IBM@IBMIL cc: ips@ece.cmu.edu Subject: Re: iSCSI:Clear Task Set Julian, and list, The question now becomes, if we have all that carefully thought out processing that is defined in 9.4 in how to handle the other Tasks/Commands that are "In Flight", and not yet given to SCSI, how does that apply to the other Sessions with other initiators? That is, at the iSCSI Target layer we do not have the LU Number to LU mapping on any Session with any Initiator, so how do we cause the careful processing, which is defined in 9.4, to occur on the other sessions that may have and association to the subject LU? Especially since all we know is a LU Number on the Clearing Session. Perhaps we do not care about the 9.4 processing on the other Session and Other Initiators and just let SCSI layer do its thing, and at the iSCSI layer we pay no attention to the other Sessions. Do you think this is correct? . . . 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, Cell: (408) 499-9702 Internet address: hufferd@us.ibm.com Julian Satran/Haifa/IBM@IBMIL@ece.cmu.edu on 11/23/2001 07:56:36 AM Sent by: owner-ips@ece.cmu.edu To: ips@ece.cmu.edu cc: Subject: Re: iSCSI:Clear Task Set John, The LUN is just a mistake there - in all three instances it should be LU. The definitions are in accordance with SAM . There are two task management modes - tasks sets-per-initiator at each LU or common for all initiators. The mode is a SCSI issue controlled by a field in the Control-Mode page. Clear task set MAY clear all the tasks in the task set - even if common to all initiators if that is the way the task set is managed. That is also the difference between clear-task-set and abort task set. Julo John Hufferd@IBMUS 23-11-01 11:29 To: Julian Satran/Haifa/IBM@IBMIL@IBMDE cc: ips@ece.cmu.edu From: John Hufferd/San Jose/IBM@IBMUS Subject: iSCSI:Clear Task Set Julian, and List (using v 0.9) In point 9.4, just before 9.5 the Table entry associated with Clear Task Set applies to: "All tasks associated with the specified LUN and initiator. For all other initiators all tasks at LUN with no regard to order." Perhaps we mean LU here, but I know that the iSCSI layer does not have information about LU, only about the LU Number (LUN) in the command. We can not tell, at the iSCSI layer, if the LU represented by a LUN on Session 1, has any relationship to any LUN on any other session. This is because each initiator may have their own numbering for LUs. Therefore, do we just pass the Clear Task Set to the SCSI layer and hope for the best, or does the iSCSI layer also suppose to apply the Clear Task Set to all the sessions that it has coming into the iSCSI (SCSI) Target Port? If the latter, again how will that work when the iSCSI layer has no idea what LU an Initiator's LUN will map to? . . . 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, Cell: (408) 499-9702 Internet address: hufferd@us.ibm.com
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