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Re: [Qemu-devel] Comparison of virtual disks?
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] Comparison of virtual disks? |
Date: |
Mon, 04 May 2015 14:27:46 +0200 |
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Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 |
On 04/05/2015 13:14, Max Reitz wrote:
> I'm sorry, but I don't know whether such a chart exists (the closest
> thing I know is http://en.wikipedia.org/wiki/Category:Disk_images -
> which is not very close...). However, the general assumption we as
> developers are working with is that if the user's top priority is
> performance, they should use raw; and if they want to use all of the
> features qemu's block layer provides, they should use qcow2. All other
> formats are implemented merely for compatibility and ideally they should
> not be used for running VMs, but only for converting them to qcow2 using
> qemu-img convert.
In addition to this, there are a bunch of image formats that have good
read performance: I can think of vhdx, vmdk, vdi. These can be used as
backing images for qcow2, for example the virt-v2v tool uses this trick
to convert Hyper-V and VMware images without copying them first.
Paolo