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Date:   Mon, 14 Mar 2022 08:36:44 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Adam Manzanares <a.manzanares@samsung.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Pankaj Raghav <p.raghav@samsung.com>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Javier =?iso-8859-1?Q?Gonz=E1lez?= <javier.gonz@samsung.com>,
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        Jens Axboe <axboe@kernel.dk>, Keith Busch <kbusch@kernel.org>,
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Subject: Re: [PATCH 0/6] power_of_2 emulation support for NVMe ZNS devices
Message-ID: <20220314073644.GB4204@lst.de>
References: <CGME20220308165414eucas1p106df0bd6a901931215cfab81660a4564@eucas1p1.samsung.com> <20220308165349.231320-1-p.raghav@samsung.com> <20220310094725.GA28499@lst.de> <20220310173835.GB89599@bgt-140510-bm01>
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On Thu, Mar 10, 2022 at 05:38:35PM +0000, Adam Manzanares wrote:
> > Do these drives even support Zone Append?
> 
> Should it matter if the drives support append? SMR drives do not support append
> and they are considered zone block devices. Append seems to be an optimization
> for users that want higher concurrency per zone. One can also build concurrency
> by leveraging multiple zones simultaneously as well.

Not supporting it natively for SMR is a major pain.  Due to hard drives
being relatively slow the emulation is somewhat workable, but on SSDs
the serialization would completely kill performance.