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Date: Thu, 27 Jul 2006 17:30:53 +0200
From: =?ISO-8859-1?Q?Dieter_St=FCken?= <stueken@conterra.de>
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Subject: Re: [linux-lvm] Performance impact of LVM
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To: LVM general discussion and development <linux-lvm@redhat.com>

Sander Smeenk wrote:
> I've recently subscribed here as i have some questions about LVM,
> particularly the performance impact of LVM on disk IO.

impact? no, I don't think so.

LVM does not interfere with the IO system too much.
For an IO request LVM decides where (device/sector)
to find the data. The transfer of the data itself,
to or from the device, happens as before, without LVM.
I think the delay for the lookup to find the data
is negligible compared to the transfer time itself.

But LVM may improve the performance indirectly, if
you spread your data over several disk by using striping.
But this is not guaranteed and depends on the structure
of your data and the access pattern.

there are several studies about this topic, i.E:

http://www.suse.com/en/whitepapers/lvm/lvm1.html#perf

.. although, its a bit outdated, as they still use LVM1... 

Dieter.