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Re: [Xen-users] Which is fastest for Xen disks: LVM, Qcow2 or Image-bas

To: Thiago Vinhas <thiago@xxxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] Which is fastest for Xen disks: LVM, Qcow2 or Image-based VM?
From: "Fajar A. Nugraha" <fajar@xxxxxxxxx>
Date: Thu, 8 Oct 2009 10:09:17 +0700
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2009/10/8 Thiago Vinhas <thiago@xxxxxxxxxxxxxxxx>
> Is there any benchmark or does anyone have tried which one is fastest?

Assuming everything else is equal, definitely LVM (or partition, or
physical disk)

The other ones would experience file system operation overhead (due to
the fact that the disk image is stored as files).
As to how much the difference is, better try your self. Last time I
tested with tap:aio on disk image and do I/O-intensive operations,
dom0 runs out of memory and become incredibly slow :P

Some other things to consider :
- using sparse disk image would yield lower performance compared to
fully-alocated disk image
- testing with small disk image (i.e. smaller than available dom0
memory) can show higher result due to dom0 caching efect.


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