FW: FW: persistent reservations follow-up question

Ulrich, David dulrich at lsil.com
Fri Nov 14 11:40:15 PST 2003


* From the T10 Reflector (t10 at t10.org), posted by:
* "Ulrich, David" <dulrich at lsil.com>
*
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Hi Charles,=20

I had a very similar question at one time and got this reply from
George.  I'm sure the wording has changed since then, but this was the
original intent.

David Ulrich=20
LSI Logic Storage Systems Division (today)=20

-----Original Message-----=20
From: George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com=20
[ mailto:George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com
<mailto:George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com> ]=20
Sent: Friday, December 01, 2000 8:04 PM=20
To: Ulrich, David=20
Cc: 't10 at t10.org'=20
Subject: Re: FW: persistent reservations follow-up question=20


David,=20

Not really. You can look at in one of two ways, both end in the same=20
result.=20
-The target does the preempt by clearing the reservation and
registration=20
then establishing a new reservation and new registration before
completing=20
the operation. The new reservation would be defined by the type and
scope=20
fields and the new registration key would be the reservation key fields =

value. OR=20
- The target does the preempt by clearing the reservation and does
nothing=20
with the registration. It knows not to do anything because the
reservation=20
key and the service action reservation key are equal. Because they are=20
equal the target knows only the reservation type and scope are going to
be=20
changed. This is all allowed because to the following statement in
section=20
5.5.3.6.3.3:=20

A PERSISTENT RESERVE OUT specifying a PREEMPT service action with the=20
SERVICE ACTION RESERVATION KEY value equal to the reservation key is =
not
an=20
error. In that case the device server shall establish the new
reservation.=20

Bye for now,=20
George Penokie=20

Dept 2C6  114-2 N212=20
E-Mail:    gpenokie at tivoli.com=20
Internal:  553-5208=20
External: 507-253-5208   FAX: 507-253-2880=20


"Ulrich, David" <dulrich at lsil.com>@t10.org on 11/29/2000 11:11:55 AM=20

Sent by:  owner-t10 at t10.org=20


To:   "'t10 at t10.org'" <t10 at t10.org>=20
cc:=20
Subject:  FW: persistent reservations follow-up question=20





George,=20

Thanks for the reply.=20

I have considered what you said below and while looking at figure 2 and =

following the flowchart another question has come to mind.  Assuming
that=20
no error conditions are encountered wouldn't we eventually come to the=20
point of removing the registration for the initiator holding the=20
reservation, which in this case also happens to be the preemptor,
removing=20
the reservation, and then attempting create a new reservation for the=20
initiator we just removed the registration information for?=20

Regards,=20
David Ulrich=20

-----Original Message-----=20
From: George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com=20
[ mailto:George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com
<mailto:George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com> ]=20
Sent: Monday, November 27, 2000 10:00 AM=20
To: Ulrich, David=20
Cc: 't10 at t10.org'=20
Subject: Re: persistent reservations=20

* From the T10 Reflector (t10 at t10.org), posted by:=20
* George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com=20
*=20
David,=20
The logical unit would respond as no differently than if the PREEMPT =
AND

ABORT came from an initiator that did not hold the reservation. (i.e.,
it=20
would follow the flow chart in figure 2 to preempt and the description
in=20
section 5.5.3.6.4 to abort.=20

Bye for now,=20
George Penokie=20

Dept 2C6  114-2 N212=20
E-Mail:    gpenokie at tivoli.com=20
Internal:  553-5208=20
External: 507-253-5208   FAX: 507-253-2880=20

"Ulrich, David" <dulrich at lsil.com>@t10.org on 11/20/2000 09:52:51 AM=20

Sent by:  owner-t10 at t10.org=20

To:   "'t10 at t10.org'" <t10 at t10.org>=20
cc:=20
Subject:  persistent reservations=20




Is there any behavior defined if an initiator issues a PREEMPT AND =
ABORT

command to a logical unit that it has reserved?=20



*=20
* For T10 Reflector information, send a message with=20
* 'info t10' (no quotes) in the message body to majordomo at t10.org=20





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 FW: FW: persistent reservations follow-up question Hi Charles, I had a very similar question at one time and got = this reply from George.  I'm sure the wording has changed since = then, but this was the original intent. David Ulrich 
LSI Logic Storage Systems Division (today) -----Original Message----- 
From: = George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com 
[= mailto:George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com] 
Sent: Friday, December 01, 2000 8:04 PM 
To: Ulrich, David 
Cc: 't10 at t10.org' 
Subject: Re: FW: persistent reservations follow-up = question 
David, Not really. You can look at in one of two ways, both = end in the same 
result. 
-The target does the preempt by clearing the = reservation and registration 
then establishing a new reservation and new = registration before completing 
the operation. The new reservation would be defined = by the type and scope 
fields and the new registration key would be the = reservation key fields 
value. OR 
- The target does the preempt by clearing the = reservation and does nothing 
with the registration. It knows not to do anything = because the reservation 
key and the service action reservation key are = equal. Because they are 
equal the target knows only the reservation type and = scope are going to be 
changed. This is all allowed because to the = following statement in section 
5.5.3.6.3.3: A PERSISTENT RESERVE OUT specifying a PREEMPT service = action with the 
SERVICE ACTION RESERVATION KEY value equal to the = reservation key is not an 
error. In that case the device server shall = establish the new reservation. Bye for now, 
George Penokie Dept 2C6  114-2 N212 
E-Mail:    gpenokie at tivoli.com 
Internal:  553-5208 
External: 507-253-5208   FAX: = 507-253-2880 
;Ulrich, David; = <dulrich at lsil.com>@t10.org on 11/29/2000 11:11:55 AM Sent by:  owner-t10 at t10.org 
To:   ;'t10 at t10.org'; = <t10 at t10.org> 
cc: 
Subject:  FW: persistent reservations follow-up = question 



George, Thanks for the reply. I have considered what you said below and while = looking at figure 2 and 
following the flowchart another question has come to = mind.=A0 Assuming that 
no error conditions are encountered wouldn't we = eventually come to the 
point of removing the registration for the initiator = holding the 
reservation, which in this case also happens to be = the preemptor, removing 
the reservation, and then attempting create a new = reservation for the 
initiator we just removed the registration = information for? Regards, 
David Ulrich -----Original Message----- 
From: = George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com 
[= mailto:George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com] 
Sent: Monday, November 27, 2000 10:00 AM 
To: Ulrich, David 
Cc: 't10 at t10.org' 
Subject: Re: persistent reservations * From the T10 Reflector (t10 at t10.org), posted = by: 
* = George_Penokie/Tivoli_Systems%TIVOLI_SYSTEMS at us.ibm.com 
* 
David, 
The logical unit would respond as no differently = than if the PREEMPT AND 
ABORT came from an initiator that did not hold the = reservation. (i.e., it 
would follow the flow chart in figure 2 to preempt = and the description in 
section 5.5.3.6.4 to abort. Bye for now, 
George Penokie Dept 2C6=A0 114-2 N212 
E-Mail:=A0=A0=A0 gpenokie at tivoli.com 
Internal:=A0 553-5208 
External: 507-253-5208=A0=A0 FAX: = 507-253-2880 ;Ulrich, David; = <dulrich at lsil.com>@t10.org on 11/20/2000 09:52:51 AM Sent by:=A0 owner-t10 at t10.org To:=A0=A0 ;'t10 at t10.org'; = <t10 at t10.org> 
cc: 
Subject:=A0 persistent reservations 


Is there any behavior defined if an initiator issues = a PREEMPT AND ABORT 
command to a logical unit that it has = reserved? 

* 
* For T10 Reflector information, send a message = with 
* 'info t10' (no quotes) in the message body to = majordomo at t10.org 



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