From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shaohua Li <shli@kernel.org>
Subject: Re: [PATCH 0/2] md: Add support for Multiple PPLs
Date: Mon, 28 Aug 2017 07:54:10 -0700
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To: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Cc: Pawel Baldysiak <pawel.baldysiak@intel.com>, linux-raid@vger.kernel.org
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On Mon, Aug 28, 2017 at 09:44:20AM +0200, Artur Paszkiewicz wrote:
> On 08/25/2017 11:53 PM, Shaohua Li wrote:
> > On Fri, Aug 25, 2017 at 10:02:07PM +0200, Pawel Baldysiak wrote:
> >> On 08/21/2017 06:14 PM, Shaohua Li wrote> Can you elaborate more?
> >>>
> >> Storage presented to the host may have a RAID on the back-end. For NVMe
> >> SSDs, the 1.3 specification provided a field to advertise chunk
> >> boundaries: Identify Namespace NOIOB. We need to span the entire stripe
> >> to utilize the total available capacity, otherwise we'll repeatedly
> >> write to only a subset, increasing write amplification factor. The new
> >> PPL approach is designed to access the full capacity.
> > 
> > Ok, this makes sense. The 1MB area looks arbitrary though. What if the
> > chunk is 2MB? Could we make it configurable?
> 
> Actually, it is configurable by 'ppl_size' which comes from mdadm. The
> 1MB is what the current RSTe standard defines but it will be possible to
> change it without affecting the kernel.

ok, queued the patches, thanks!