SAS STP: maintaining affiliations through SATA/SAS changes

Sheffield, Robert L robert.l.sheffield at intel.com
Thu Jan 30 08:00:46 PST 2003


* From the T10 Reflector (t10 at t10.org), posted by:
* "Sheffield, Robert L" <robert.l.sheffield at intel.com>
*
I agree that anytime the link rate might change, a CHANGE is called for. An STP initiator still needs a way to reset a SATA device without clearing an affiliation so as to perform recovery within the scope of an atomic access window. I think this leads to the following:
HARD RESET via SMP send change and clear affiliation
LINK RESET via SMP send change and maintain affiliation
Link reset from SATA device - send change and clear affiliation
Expander initiated link reset for any reason other than LINK RESET via SMP command - send change and clear affiliation.

Does this work?

Regards,
Bob
-----------------
Sent from my BlackBerry Handheld.

-----Original Message-----
From: Johnson, Stephen B. <sjohnson at lsil.com>
To: t10 at t10.org <t10 at t10.org>
Sent: Thu Jan 30 06:13:54 2003
Subject: RE: SAS STP: maintaining affiliations through SATA/SAS changes

* From the T10 Reflector (t10 at t10.org), posted by:
* "Johnson, Stephen B." <sjohnson at lsil.com>
*
For an SSP device an expander-initiated link reset SHOULD cause a CHANGE to
be sent.
This will inform all the initiators the SSP device was reset so they can
clean up their respective
outstanding commands.

Steve

-----Original Message-----
From: Sheffield, Robert L [mailto:robert.l.sheffield at intel.com]
Sent: Wednesday, January 29, 2003 6:34 PM
To: thoglund at lsil.com; Elliott at hp.com; t10 at t10.org
Subject: Re: SAS STP: maintaining affiliations through SATA/SAS changes


* From the T10 Reflector (t10 at t10.org), posted by:
* "Sheffield, Robert L" <robert.l.sheffield at intel.com>
*
I think anytime an expander generates a CHANGE due to an event on a port, it
should clear any active affiliations on that port. Does an
expander-initiated link reset cause a CHANGE to be sent? I hope not. The
intent was to provide a way for an STP initiator to reset a SATA device
without clearing its own affiliation.

Bob
-----------------
Sent from my BlackBerry Handheld.

-----Original Message-----
From: Hoglund, Tim <thoglund at lsil.com>
To: 'Elliott, Robert (Server Storage)' <Elliott at hp.com>; t10 at t10.org
<t10 at t10.org>
Sent: Wed Jan 29 15:24:11 2003
Subject: RE: SAS STP: maintaining affiliations through SATA/SAS changes

How about:
 
Expander initiated link reset sequence keeps affiliation.
Wire-initiated OOB clears affiliation (assume SATA drive won't initiate OOB
after it's up and running)
 
In this manner initiators issuing link reset via SMP can keep affiliation.
If a SAS drive is plugged in then affiliation is cleared as it should be.
If a SATA drive is plugged in then affiliation is cleared, assume hot-plug
event, initiators must resolve ownership.
 
TimH



~~~~~~~~~~~~~~~~~~~~~~~ 
Tim.Hoglund at lsil.com 
719/533-7450 (Voice) 
719/533-7480 (Fax) 
~~~~~~~~~~~~~~~~~~~~~~~ 

-----Original Message-----
From: Elliott, Robert (Server Storage) [mailto:Elliott at hp.com]
Sent: Wednesday, January 29, 2003 3:14 PM
To: t10 at t10.org
Subject: SAS STP: maintaining affiliations through SATA/SAS changes



The current text in 9.3.2 indicates STP affiliations are maintained until
expander power off, SMP PHY CONTROL requests to change them, or CLOSE (CLEAR
AFFILIATION).

It specifically mentions that link reset sequences (e.g. from removing the
SATA device) do not change affiliations. 

If a SATA device is pulled and a SAS port shows up in its place, do we want
the expander to continue maintaining the affiliation?  It obviously should
not not block OPENs headed to the SAS port.  If the SAS port is removed and
a SATA device is put back, should the affiliation still be there?


-- 
Rob Elliott, elliott at hp.com 
Hewlett-Packard Industry Standard Server Storage Advanced Technology 
 <https://ecardfile.com/id/RobElliott> https://ecardfile.com/id/RobElliott 




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