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Date: Mon, 24 Apr 2017 20:19:33 +0800
From: Fam Zheng <famz@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v6] migration/block: use blk_pwrite_zeroes
 for each zero cluster
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To: 858585 jemmy <jemmy858585@gmail.com>
Cc: qemu block <qemu-block@nongnu.org>, Juan Quintela <quintela@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Dave Gilbert <dgilbert@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Lidong Chen <lidongchen@tencent.com>

On Mon, 04/24 20:09, Fam Zheng wrote:
> It's a separate problem.

To be specific:

1) there is an option "overlap-check" that one can use to
disable the costly metadata check;

2) qcow2 with cluster_size = 512 is probably too uncommon to be optimized for.

Both are irrelevant to why and how this patch can be improved, IMO.

Fam