[vfio-users] setting up virtual disks

Patrick O'Callaghan poc at usb.ve
Tue Mar 28 13:41:33 UTC 2017


On Tue, 2017-03-28 at 15:08 +0200, Laszlo Ersek wrote:
> On 03/28/17 14:21, Patrick O'Callaghan wrote:
> > On Tue, 2017-03-28 at 11:47 +0200, Laszlo Ersek wrote:
> > > I recommend the following setup:
> > > 
> > > - hard disk(s):          virtio-blk or virtio-scsi disk, as you prefer
> > 
> > I'm interested in why someone would prefer one over the other. Can you
> > explain?
> 
> I prefer virtio-scsi because it supports thin provisioning (UNMAP scsi
> operation); it lets me conserve space in host filesystems that support
> discard (such as ext4 or xfs, for example -- there may be more). Given
> the right configuration, if you delete files in your Windows 8 or
> Windows 10 VM, the space is eventually released on the host filesystem.

OK, thanks.

> With virtio-blk, the software stack is less featureful and thereby
> thinner, which is said by some to lead to better performance. Also, as
> far as I know, dataplane is only available for virtio-blk at the moment,
> it is in progress for virtio-scsi. (I could be out of date on that
> though.) YMMV.

No idea what that is. As I'm not provisioning multiple high-load
servers, does this matter to me?

poc




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