From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Thornber <thornber@redhat.com>
Subject: Re: dm-thin vs lvm performance
Date: Fri, 20 Jan 2012 17:33:34 +0000
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On Fri, Jan 20, 2012 at 05:03:35PM +0000, Joe Thornber wrote:
> For me, the first run of aio_stress manages a throughput of ~9G/s.
> After the wipe, which is just a simple dd across the device,
> performance drops to ~5.5 G/s.  Also throughput on the device under
> the linear target also drops.  Permanently.
> 
> I don't know if this is specific to aio, or a more general slowdown.

It's just me being stupid.  For the initial pass the ramdisk has no
memory backing it and is just returning zeroes.

Back to testing ...

- Joe