Approved: steve
MIME-Version: 1.0
Content-Type: multipart/alternative;
Subject: RE: CLEAR TASK SET task management function
Date: Thu, 1 Mar 2007 18:18:48 -0700
From: "Ian Davies" <Ian.Davies@dothill.com>
To: "Elliott, Robert \(Server Storage\)" <Elliott@hp.com>
Cc: <t10@t10.org>

This is a multi-part message in MIME format.

------_=_NextPart_001_01C75C68.BB464776
Content-Type: text/plain;
        charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

Dot Hill external RAID controllers use the clear task set TMF for the
same reason.

=20

________________________________

From: owner-t10@t10.org [mailto:owner-t10@t10.org] On Behalf Of Charles
Binford
Sent: Tuesday, February 27, 2007 7:56 AM
To: Elliott, Robert (Server Storage)
Cc: t10@t10.org
Subject: Re: CLEAR TASK SET task management function

=20

Rob - we have found Clear Task Set useful for the following scenario:=20

*       simple jbod config accessed via FC switch=20
*       commands in progress on side A, and a link goes down that gives
access to side A. =20
*       if it is the host side of the switch with the link down, the
drive doesn't know about it=20
*       the host retries the commands via side B, but the drive has its
buffer and dma resources tied up waiting for the IOs to complete via
side A=20
*       a Clear Task Set clears up this situation=20


A LUN Reset would do the same, but it is a bigger hammer than necessary
because, as you say below it clears other state info.

cb



On Fri, 2007-02-23 at 14:50 -0600, Elliott, Robert (Server Storage)
wrote:=20

=20
Does any SCSI software other than test software actually use the CLEAR
TASK
SET task management function? CLEAR TASK SET clears tasks from all I_T
nexuses.
=20
If so, would that software be happy to use one of these instead?=20
a) ABORT TASK SET - just clear tasks from the same I_T nexus; or=20
b) LOGICAL UNIT RESET - clear tasks from all I_T nexuses and wipe out
other
state information=20
=20
--
Rob Elliott, elliott@hp.com
Hewlett-Packard Industry Standard Server Storage Advanced Technology
https://ecardfile.com/id/RobElliott
=20
=20

------_=_NextPart_001_01C75C68.BB464776
Content-Type: text/html;
        charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

xmlns:o=3D"urn:schemas-microsoft-com:office:office" = xmlns:w=3D"urn:schemas-microsoft-com:office:word" = xmlns:x=3D"urn:schemas-microsoft-com:office:excel" = xmlns:p=3D"urn:schemas-microsoft-com:office:powerpoint" = xmlns:oa=3D"urn:schemas-microsoft-com:office:activation" = xmlns=3D"http://www.w3.org/TR/REC-html40">

Dot Hill external RAID controllers use the clear task set TMF = for the same reason.

 

From: owner-t10@t10.org [mailto:owner-t10@t10.org] On Behalf Of Charles Binford
Sent: Tuesday, February = 27, 2007 7:56 AM
To: Elliott, Robert = (Server Storage)
Cc: t10@t10.org
Subject: Re: CLEAR TASK = SET task management function

 

Rob - we have found Clear Task Set useful for the following = scenario:

A LUN Reset would do the same, but it is a bigger hammer than necessary because, as you say below it clears other state info.

cb



On Fri, 2007-02-23 at 14:50 -0600, Elliott, Robert (Server Storage) = wrote: 

 

Does any SCSI software other than =
test software actually use the CLEAR =
TASK

SET task management function? =
CLEAR TASK SET clears tasks from all =
I_T

nexuses.<=
/pre>
 

If so, would that software be =
happy to use one of these instead? =


a) ABORT TASK SET - just clear =
tasks from the same I_T nexus; or =


b) LOGICAL UNIT RESET - clear =
tasks from all I_T nexuses and wipe out =
other

state information =


 

--
<= pre>Rob Elliott, elliott@hp.com

Hewlett-Packard Industry Standard =
Server Storage Advanced =
Technology

https://ecardfile.com/id/Rob=
Elliott

 

 
------_=_NextPart_001_01C75C68.BB464776--