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Hello!
Bumping up this thread as there've been some updates in the specs
discussion [1] regarding native AIO stability & performance.
Seems there's also movement in the related qemu development (see inline
comments).
Best regards
Silvan

[1]
https://review.openstack.org/#/c/232514/7/specs/mitaka/approved/libvirt-aio-mode.rst,cm


2015-11-17 14:36 GMT+01:00 Alexander Schmidt <alexs at linux.vnet.ibm.com>:

> On Tue, 17 Nov 2015 11:14:29 +0100
> Alexander Schmidt <alexs at linux.vnet.ibm.com> wrote:
>
> > Hi all,
> >
> > I started a blueprint [1] and spec [2] for enabling the usage
> > of native AIO mode for disk devices. The idea is to enable it
> > for storage backends/setups where IO performance benefits from
> > using native AIO mode and where no downsides are known wrt
> > stability or data integrity.
> >
> > As there is a wide range of storage backends and setups, I'm
> > looking for input on specific backends that are known to
> > benefit from native AIO mode (or where known problems exist).
> > These are the comments so far (copied from the spec):
> >
> > * native AIO mode is a bad idea if the storage is not fully
> >   pre-allocated, e.g. for qcow2 images that grow on
> >   demand or sparse LVM storage
> > * AIO mode has no effect if using the in-qemu
> >   network clients (any disks that use <disk type='network'>).
> >   It is only relevant if using the in-kernel network drivers
> >
> > Cases where AIO mode is beneficial
> >
> > * Raw images and pre-allocated images in qcow2 format
> > * Cinder volumes that are located on iSCSI, NFS or FC devices.
> > * Quobyte (reported by Silvan Kaiser)
> >
> > Also input on the minimum libvirt/qemu version where native
> > AIO mode should be used would be very helpful.
> >
> > Thanks and regards,
> > Alex
> >
>
> Adding the links...
>
> [1] https://blueprints.launchpad.net/nova/+spec/libvirt-aio-mode
>
> [2] https://review.openstack.org/#/c/232514/
>
>
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-- 
Dr. Silvan Kaiser
Quobyte GmbH
Hardenbergplatz 2, 10623 Berlin - Germany
+49-30-814 591 800 - www.quobyte.com<http://www.quobyte.com/>
Amtsgericht Berlin-Charlottenburg, HRB 149012B
Management board: Dr. Felix Hupfeld, Dr. Björn Kolbeck, Dr. Jan Stender

-- 

--
*Quobyte* GmbH
Hardenbergplatz 2 - 10623 Berlin - Germany
+49-30-814 591 800 - www.quobyte.com
Amtsgericht Berlin-Charlottenburg, HRB 149012B
management board: Dr. Felix Hupfeld, Dr. Björn Kolbeck, Dr. Jan Stender
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