[ovirt-users] VirtIO-SCSI and viodiskcache custom property

[Zip]

Does it help if you edit the VM and under Resource Allocation ­ enable IO
threads. ?

Zip



From:  <users-bounces at ovirt.org> on behalf of Yaniv Kaul <ykaul at redhat.com>
Date:  Saturday, January 20, 2018 at 12:54 PM
To:  Matthias Leopold <matthias.leopold at meduniwien.ac.at>
Cc:  Wolfgang Lendl <wolfgang.lendl at meduniwien.ac.at>, Ovirt Users
<users at ovirt.org>
Subject:  Re: [ovirt-users] VirtIO-SCSI and viodiskcache custom property



On Jan 19, 2018 3:29 PM, "Matthias Leopold"
<matthias.leopold at meduniwien.ac.at> wrote:
> Hi,
> 
> is there a reason why the viodiskcache custom property isn't honored when
> using VirtIO-SCSI?
> 
> On a Cinder (Ceph) disk "viodiskcache=writeback" is ignored with VirtIO-SCSI
> and honored when using VirtIO.
> 
> On an iSCSI disk "viodiskcache=writeback" is ignored with VirtIO-SCSI and the
> VM can't be started when using VirtIO with "unsupported configuration: native
> I/O needs either no disk cache or directsync cache mode, QEMU will fallback to
> aio=threads"
> 
> We actually want to use "viodiskcache=writeback" with Cinder (Ceph) disks.

That's because on block storage we use native io and not threads. I assume
the hook needs to change to use native io in this case.
Y. 

> 
> oVirt version: 4.1.8
> 
> Thanks
> Matthias
> 
> _______________________________________________
> Users mailing list
> Users at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
> 
> 



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