From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Fri, 14 Dec 2012 14:29:53 -0500
From: Mike Snitzer <snitzer@redhat.com>
Message-ID: <20121214192953.GB3148@redhat.com>
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Subject: Re: [linux-lvm] Non 512 byte sectors
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To: Phillip Susi <psusi@ubuntu.com>
Cc: LVM general discussion and development <linux-lvm@redhat.com>

On Thu, Dec 13 2012 at 10:23am -0500,
Phillip Susi <psusi@ubuntu.com> wrote:

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> Is it possible to get dm to report > 512 byte sector size?  If so, how?

DM will automatically stack the physical and logical sector sizes based
on the devices that are assembled into the DM device.

So if you create an LV on a 4K device the associated DM device will
report the same physical and logical block size.  You can verify as much
by looking at:

/sys/block/dm-X/queue/physical_block_size
/sys/block/dm-X/queue/logical_block_size

There are more details about IO limits stacking here:
http://people.redhat.com/msnitzer/docs/io-limits.txt