zbc theory of operation

Curtis Stevens curtis.stevens at wdc.com
Tue Aug 5 08:53:52 PDT 2014


* From the T10 Reflector (t10 at t10.org), posted by:
* Curtis Stevens <curtis.stevens at wdc.com>
*
Hannes, would you please provide more information on why you need the zone
information for a given LBA?  Zone maps are fixed, but we are seeing many
drive configurations that require multiple zone types and sizes.  It is not
yet clear to me that hunting around is the best way to access these devices.
-------------------------------------------------
Curtis E. Stevens
Director, Standards & Features Technology
3355 Michelson Dr. #100
Office: 1-1041
Irvine, Ca. 92612
Phone: 949-672-7933
Cell: 949-307-5050
E-Mail: Curtis.Stevens at WDC.com
Remember, you may only be blamed for something if you are actually doing
something.
-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Hannes
Reinecke
Sent: Tuesday, August 05, 2014 5:51 AM
To: t10 at t10.org
Subject: zbc theory of operation
* From the T10 Reflector (t10 at t10.org), posted by:
* Hannes Reinecke <hare at suse.de>
*
Hi all,
I know ZBC is still far from being final, but nevertheless I've got some
questions / issues which I've stumbled across recently.
The most crucial one is how to get the zone information for any given LBA.
Typically one would use the REPORT ZONES command to retrieve the zone
information for a given LBA.
However, zbc01 states that the REPORT ZONES will fail if the LBA is _not_ the
starting LBA of a zone.
Which means we have to have an a-priory knowledge of the zone layout, ie we
have to trawl through _all_ zone information before we can use REPORT ZONES
with a non-zero LBA.
But if we have to slurp in _all_ zones before we can use the REPORT ZONES
command in a meaningful manner it makes me wonder how it is supposed to be
used.
Plus slurping in all zones upon startup takes up quite some time; I've
measured several _minutes_ to retrieve the full zone information.
So how is the REPORT ZONES command to be used without a-priory knowledge of
the zone layout?
Life would be _so much_ easier if we could lift the restriction on the REPORT
ZONES command, so that it'll always return the zone information the LBA is
contained in.
Cheers,
Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare at suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
*
* For T10 Reflector information, send a message with
* 'info t10' (no quotes) in the message body to majordomo at t10.org
*
* For T10 Reflector information, send a message with
* 'info t10' (no quotes) in the message body to majordomo at t10.org



More information about the T10 mailing list