VirtIO-SCSI and viodiskcache custom property
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. oVirt version: 4.1.8 Thanks Matthias
On Jan 19, 2018 3:29 PM, "Matthias Leopold" < matthias.leopold@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@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
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Hi, =20 is there a reason why the viodiskcache custom property isn't honored when using VirtIO-SCSI? =20 On a Cinder (Ceph) disk "viodiskcache=3Dwriteback" is ignored with VirtIO-S= CSI and honored when using VirtIO. =20 On an iSCSI disk "viodiskcache=3Dwriteback" is ignored with VirtIO-SCSI and=
--B_3599420040_119811012 Content-type: text/plain; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable Does it help if you edit the VM and under Resource Allocation =AD enable IO threads. ? Zip From: <users-bounces@ovirt.org> on behalf of Yaniv Kaul <ykaul@redhat.com> Date: Saturday, January 20, 2018 at 12:54 PM To: Matthias Leopold <matthias.leopold@meduniwien.ac.at> Cc: Wolfgang Lendl <wolfgang.lendl@meduniwien.ac.at>, Ovirt Users <users@ovirt.org> Subject: Re: [ovirt-users] VirtIO-SCSI and viodiskcache custom property On Jan 19, 2018 3:29 PM, "Matthias Leopold" <matthias.leopold@meduniwien.ac.at> wrote: the
VM can't be started when using VirtIO with "unsupported configuration: na= tive I/O needs either no disk cache or directsync cache mode, QEMU will fallba= ck to aio=3Dthreads" =20 We actually want to use "viodiskcache=3Dwriteback" 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.=20
=20 oVirt version: 4.1.8 =20 Thanks Matthias =20 _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users =20 =20
--B_3599420040_119811012 Content-type: text/html; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable <html><head></head><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: s= pace; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size:= 14px; font-family: Calibri, sans-serif;"><div><div>Does it help if you edit= the VM and under Resource Allocation – enable IO threads. ?</div><div=
<br></div><div>Zip</div><div><span class=3D"Apple-style-span" style=3D"font-siz= e: 12px; font-family: Verdana, Helvetica, Arial;"><br></span></div></div><di= v><span class=3D"Apple-style-span" style=3D"font-size: 12px; font-family: Verdan= a, Helvetica, Arial;"><br></span></div><div><span class=3D"Apple-style-span" s= tyle=3D"font-size: 12px; font-family: Verdana, Helvetica, Arial;"><br></span><= /div><span id=3D"OLK_SRC_BODY_SECTION"><div style=3D"font-family:Calibri; font-s= ize:11pt; text-align:left; color:black; BORDER-BOTTOM: medium none; BORDER-L= EFT: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in= ; BORDER-TOP: #b5c4df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt= "><span style=3D"font-weight:bold">From: </span> <<a href=3D"mailto:users-bou= nces@ovirt.org">users-bounces@ovirt.org</a>> on behalf of Yaniv Kaul <= <a href=3D"mailto:ykaul@redhat.com">ykaul@redhat.com</a>><br><span style=3D"f= ont-weight:bold">Date: </span> Saturday, January 20, 2018 at 12:54 PM<br><sp= an style=3D"font-weight:bold">To: </span> Matthias Leopold <<a href=3D"mailto= :matthias.leopold@meduniwien.ac.at">matthias.leopold@meduniwien.ac.at</a>>= ;<br><span style=3D"font-weight:bold">Cc: </span> Wolfgang Lendl <<a href=3D"= mailto:wolfgang.lendl@meduniwien.ac.at">wolfgang.lendl@meduniwien.ac.at</a>&= gt;, Ovirt Users <<a href=3D"mailto:users@ovirt.org">users@ovirt.org</a>>= ;<br><span style=3D"font-weight:bold">Subject: </span> Re: [ovirt-users] VirtI= O-SCSI and viodiskcache custom property<br></div><div><br></div><div><meta h= ttp-equiv=3D"Content-Type" content=3D"text/html; charset=3Dutf-8"><div><div dir=3D"a= uto"><div><br><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On Jan 1= 9, 2018 3:29 PM, "Matthias Leopold" <<a href=3D"mailto:matthias.leopold@med= uniwien.ac.at">matthias.leopold@meduniwien.ac.at</a>> wrote:<br type=3D"att= ribution"><blockquote class=3D"quote" style=3D"margin:0 0 0 .8ex;border-left:1px= #ccc solid;padding-left:1ex"> Hi,<br><br> is there a reason why the viodiskcache custom property isn't honored when u= sing VirtIO-SCSI?<br><br> On a Cinder (Ceph) disk "viodiskcache=3Dwriteback" is ignored with VirtIO-SCS= I and honored when using VirtIO.<br><br> On an iSCSI disk "viodiskcache=3Dwriteback" is ignored with VirtIO-SCSI and t= he VM can't be started when using VirtIO with "unsupported configuration: na= tive I/O needs either no disk cache or directsync cache mode, QEMU will fall= back to aio=3Dthreads"<br><br> We actually want to use "viodiskcache=3Dwriteback" with Cinder (Ceph) disks.<= br></blockquote></div></div></div><div dir=3D"auto"><br></div><div dir=3D"auto">= That's because on block storage we use native io and not threads. I assume t= he hook needs to change to use native io in this case. </div><div dir=3D"= auto">Y. </div><div dir=3D"auto"><br></div><div dir=3D"auto"><div class=3D"gm= ail_extra"><div class=3D"gmail_quote"><blockquote class=3D"quote" style=3D"margin:= 0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br> oVirt version: 4.1.8<br><br> Thanks<br> Matthias<br><br> ______________________________<wbr>_________________<br> Users mailing list<br><a href=3D"mailto:Users@ovirt.org" target=3D"_blank">User= s@ovirt.org</a><br><a href=3D"http://lists.ovirt.org/mailman/listinfo/users" r= el=3D"noreferrer" target=3D"_blank">http://lists.ovirt.org/mailman<wbr>/listinfo= /users</a><br><br><br></blockquote></div><br></div></div></div></div></div><= /span></body></html>
--B_3599420040_119811012--
On Mon, Jan 22, 2018 at 6:53 AM, Zip <plord@intricatenetworks.com> wrote:
Does it help if you edit the VM and under Resource Allocation – enable IO threads. ?
Confusingly, it has nothing to do with IO threads. Y.
Zip
From: <users-bounces@ovirt.org> on behalf of Yaniv Kaul <ykaul@redhat.com> Date: Saturday, January 20, 2018 at 12:54 PM To: Matthias Leopold <matthias.leopold@meduniwien.ac.at> Cc: Wolfgang Lendl <wolfgang.lendl@meduniwien.ac.at>, Ovirt Users < users@ovirt.org> Subject: Re: [ovirt-users] VirtIO-SCSI and viodiskcache custom property
On Jan 19, 2018 3:29 PM, "Matthias Leopold" <matthias.leopold@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@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Am 2018-01-20 um 19:54 schrieb Yaniv Kaul:
On Jan 19, 2018 3:29 PM, "Matthias Leopold" <matthias.leopold@meduniwien.ac.at <mailto:matthias.leopold@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.
Thank you, but i still don't quite get what's missing. We want to use the combination of Cinder (Ceph) + cache=writeback + VirtIO-SCSI. Would this be possible if aio=native was used (which is not configurable)? With iSCSI storage you still get cache=none when using VirtIO-SCSI and "viodiskcache=writeback" (and aio=native). Should i file a bug report for the Cinder disk situation? Thanks again Matthias
participants (3)
-
Matthias Leopold -
Yaniv Kaul -
Zip