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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">@john.griffith. Thanks for your information.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">I have read the BP you mentioned ([1]) and have some rough thoughts about it.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">As far as I know, the corresponding online-extend command for libvirt is “blockresize”, and for Qemu, the implement differs among disk formats.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">For the regular qcow2/raw disk file, qemu will take charge of the drain_all_io and truncate_disk actions, but for raw block device, qemu will only check if the *<b>Actual</b>* size of
the device is larger than current size. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New"">I think the former need more consideration, because the extend work is done by libvirt, Nova may need to do this first and then notify Cinder.
But if we take allocation limit of different cinder backend drivers (such as quota, nfs_used_ratio, nfs_oversub_ratio, etc) into account, the workflow will be more complicated.
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New"">This scenario is not included by the Item 3 of BP ([1]), as it cannot be simply “just work” or notified by the compute node/libvirt after
the volume is extended.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New"">This regular qcow2/raw disk files are normally stored in file system based storage, maybe the Manila project is more appropriate for this
scenario?<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New"">Thanks.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:6.0pt;text-indent:-6.0pt"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">[1]: <a href="https://blueprints.launchpad.net/cinder/+spec/inuse-extend-volume-extension">https://blueprints.launchpad.net/cinder/+spec/inuse-extend-volume-extension</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D">----------<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D">zhangleiqiang<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D">Best Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.5pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> John Griffith [mailto:john.griffith@solidfire.com]
<br>
<b>Sent:</b> Tuesday, March 04, 2014 1:05 AM<br>
<b>To:</b> OpenStack Development Mailing List (not for usage questions)<br>
<b>Cc:</b> Luohao (brian)<br>
<b>Subject:</b> Re: [openstack-dev] [Cinder] Do you think we should introduce the online-extend feature to cinder ?<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">On Mon, Mar 3, 2014 at 2:01 AM, Zhangleiqiang <<a href="mailto:zhangleiqiang@huawei.com" target="_blank">zhangleiqiang@huawei.com</a>> wrote:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Hi, stackers:<br>
<br>
Libvirt/qemu have supported online-extend for multiple disk formats, including qcow2, sparse, etc. But Cinder only support offline-extend volumes currently.<br>
<br>
Offline-extend volume will force the instance to be shutoff or the volume to be detached. I think it will be useful if we introduce the online-extend feature to cinder, especially for the file system based driver, e.g. nfs, glusterfs, etc.<br>
<br>
Is there any other suggestions?<br>
<br>
Thanks.<br>
<br>
<br>
----------<br>
zhangleiqiang<br>
<br>
Best Regards<br>
<br>
<br>
_______________________________________________<br>
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<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">Hi Zhangleiqiang,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">So yes, there's a rough BP for this here: [1], and some of the folks from the Trove team (pdmars on IRC) have actually started to dive into this. Last I checked with him there were some
sticking points on the Nova side but we should synch up with Paul, it's been a couple weeks since I've last caught up with him.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">Thanks,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">John<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">[1]: <a href="https://blueprints.launchpad.net/cinder/+spec/inuse-extend-volume-extension">https://blueprints.launchpad.net/cinder/+spec/inuse-extend-volume-extension</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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