<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Oct 30, 2017 at 6:16 PM, Martin Polednik <span dir="ltr"><<a href="mailto:mpoledni@redhat.com" target="_blank">mpoledni@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">As stated previously, 1 IO thread is somewhat sane choice. Multiple IO<br>
threads make sense if you have multiple storage devices across<br>
different NUMA nodes.<br>
<br>
mpolednik<br>
<div class="gmail-m_5802962169176706901gmail-HOEnZb"><div class="gmail-m_5802962169176706901gmail-h5"><br>
On Mon, Oct 30, 2017 at 4:29 PM, Darrell Budic <<a href="mailto:budic@onholyground.com" target="_blank">budic@onholyground.com</a>> wrote:<br>
> Best explanation I’ve found is<br>
> <a href="https://wiki.mikejung.biz/KVM_/_Xen#virtio-blk_iothreads_.28x-data-plane.29" rel="noreferrer" target="_blank">https://wiki.mikejung.biz/KVM_<wbr>/_Xen#virtio-blk_iothreads_.28<wbr>x-data-plane.29</a><br><br></div></div></blockquote><div><br></div><div>[snip]</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="gmail-m_5802962169176706901gmail-HOEnZb"><div class="gmail-m_5802962169176706901gmail-h5">
><br>
> I currently enable it on all VMs and assign 1 thread per drive on my<br>
> systems.<br><br></div></div></blockquote><div><br></div><div>Thanks for sharing your experience, Darrell. </div><div>I'm testing some VMs with Oracle RDBMS where I configured 3 disks with virtio-scsi and now I have assigned 3 IO threads. Let's see the numbers.</div><div>In the mean time I verified you have to deactivate/activate the disks in the guest, otherwise you do get 3 SCSI controllers, but all the 3 disks are bound to the first one (scsi0-0-0-0).</div><div>Now instead on hypervisor I correctly get this with dumpxml:</div><div><br></div><div># virsh -r dumpxml my_guest | grep scsi</div><div> <target dev='sda' bus='scsi'/></div><div> <alias name='scsi0-0-0-0'/></div><div> <target dev='sdb' bus='scsi'/></div><div> <alias name='scsi1-0-0-0'/></div><div> <target dev='sdc' bus='scsi'/></div><div> <alias name='scsi2-0-0-0'/></div><div> <controller type='scsi' index='0' model='virtio-scsi'></div><div> <alias name='scsi0'/></div><div> <controller type='scsi' index='1' model='virtio-scsi'></div><div> <alias name='scsi1'/></div><div> <controller type='scsi' index='2' model='virtio-scsi'></div><div> <alias name='scsi2'/></div><div># </div><div><br></div><div>Martin, I have not understood when you write about "if you have multiple storage devices across different NUMA nodes."</div><div>Can you elaborate a bit or point to any documentation link?</div><div><br></div><div>Thanks,</div><div>Gianluca</div><div><br></div></div></div></div>