SPC-5 and SBC-3 documents posted in support of ZBC

Gerry Houlder gerry.houlder at seagate.com
Wed Jan 8 08:28:05 PST 2014


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1401084_f.htm">HTML-formatted message</a>

I expect T10 discussion will bring up concerns (that i have heard from at
least one systems company) about whether the proposed INQUIRY field should
allow recognition of "SBC device" (the zero case), autonomous SMR, host
assisted SMR, and ZBC device. The justification i have heard for wanting
such recognition is that they may use the information to determine which
tier to assign the drive to. For example, SBC device = tier 1, autonomous =
tier 2, host assisted = tier 2 or 3 (depending on system requirements), ZBC
= tier 3. Most folks don't see the need for all of these cases, but I'd
like to listen to the discussion on this. Some systems use the RPM
indicator in the block device characteristics VPD page to make this choice
today, so this new field would add more detail to the tier assignment
choice.
On Wed, Jan 8, 2014 at 9:51 AM, Ralph Weber <Ralph.Weber at wdc.com> wrote:
>  Calvin,
>
>
>
> Here is what I think the answer to your question(s) looks like.
>
>
>
>
>
> Device type
>
> HAS_ZBC
>
> Autonomous (aka Transparent) SMR
>
> SBC
>
> 0
>
> Host Assisted SMR
>
> SBC
>
> 1
>
> Restricted SMR
>
> ZBC
>
> ???
>
>
>
> Of course, there is a high probability that I am wrong.
>
>
>
> All the best,
>
>
>
> .Ralph
>
>
>
> *From:* owner-t10 at t10.org [mailto:owner-t10 at t10.org] *On Behalf Of *Gerry
> Houlder
> *Sent:* Wednesday, January 08, 2014 8:52 AM
> *To:* Calvin Chen
> *Cc:* t10 at t10.org
> *Subject:* Re: SPC-5 and SBC-3 documents posted in support of ZBC
>
>
>
> Current plan is autonomous drives and host assisted SMR drives will have
> direct access device type while restricted SMR will have the new ZBC device
> type. A field in the block device characteristics VPD page will allow
> differentiation of host assisted versus restricted SMR types.
>
>
>
> On Tue, Jan 7, 2014 at 4:30 PM, Calvin Chen <cachen at microsoft.com> wrote:
>
> Hi Ralph,
>
>
>
> I have couple questions regarding the proposed SMR device identification
> spec.
>
>
>
> 1.	   Will autonomous SMR, host assisted SMR and restricted SMR target
> device share using the same Peripheral device type 14h = ZBC – Zoned block
> device?
>
> 2.	   If a storage target device has the HAS_ZBC bit set to 0 and
> Peripheral device type 14h = ZBC, does it mean the storage target device is
> a restricted SMR drive?
>
>
>
> Thanks
> Calvin
>
>
>
>
>
> *From:* owner-t10 at t10.org [mailto:owner-t10 at t10.org] *On Behalf Of *Ralph
> Weber
> *Sent:* Monday, January 6, 2014 6:34 PM
> *To:* t10 at t10.org
> *Subject:* SPC-5 and SBC-3 documents posted in support of ZBC
>
>
>
> As requested by today's ZBC call, two documents are being posted for
> January CAP consideration.
>
> SPC-5: Assign device type code to ZBC
> http://www.t10.org/cgi-bin/ac.pl?t=d&f=14-017r0.pdf
>
> SBC-4: Update Block Device Characteristics VPD page for ZBC
> http://www.t10.org/cgi-bin/ac.pl?t=d&f=14-018r0.pdf
>
> See you in Irvine,
>
> .Ralph
>
>
>



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