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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks Alessandro, I have also updated the etherpad (</span><a href="https://etherpad.openstack.org/summit-havana-cinder-multi-attach-and-ro-volumes">https://etherpad.openstack.org/summit-havana-cinder-multi-attach-and-ro-volumes</a><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">)
to include the latest findings regarding R/O volumes. It appears that a number of hypervisors do indeed allow for setting the volumes to read only.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Kurt Martin<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> Alessandro Pilotti [mailto:ap@pilotti.it]
<br>
<b>Sent:</b> Monday, May 13, 2013 10:46 AM<br>
<b>To:</b> OpenStack Development Mailing List<br>
<b>Subject:</b> Re: [openstack-dev] [cinder] About Read-Only volume support<br>
<b>Importance:</b> High<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:13.5pt;font-family:"Helvetica","sans-serif";color:black">Hi guys,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:13.5pt;font-family:"Helvetica","sans-serif";color:black">"Summit feedback: Not doing R/O volumes due to the limited hypervisor<br>
that can support setting the volume to R/O, currently only KVM has<br>
this capability".<o:p></o:p></span></p>
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<p class="MsoNormal">Hyper-V supports mounting R/O iSCSI volumes as well.<o:p></o:p></p>
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<p class="MsoNormal">Alessandro<o:p></o:p></p>
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<p class="MsoNormal">On May 13, 2013, at 13:22 , <a href="mailto:lzy.dev@gmail.com">
lzy.dev@gmail.com</a> wrote:<o:p></o:p></p>
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<p class="MsoNormal">Hi All,<br>
<br>
In <a href="https://etherpad.openstack.org/summit-havana-cinder-multi-attach-and-ro-volumes">
https://etherpad.openstack.org/summit-havana-cinder-multi-attach-and-ro-volumes</a>,<br>
I saw a comment there:<br>
"Summit feedback: Not doing R/O volumes due to the limited hypervisor<br>
that can support setting the volume to R/O, currently only KVM has<br>
this capability".<br>
<br>
I agree there probably have some troubles cause R/O volumes support<br>
hard to implement.<br>
But maybe since I have not attended the summit, nova and cinder guys<br>
not notice there is a blueprint to plan to implement a cinder backend<br>
driver for glance<br>
(<a href="https://blueprints.launchpad.net/glance/+spec/glance-cinder-driver">https://blueprints.launchpad.net/glance/+spec/glance-cinder-driver</a>, I<br>
proposed), so I consider the R/O volumes support can be implemented<br>
gracefully.<br>
Under the case, the R/O volume stored in cinder will be created as an<br>
image, client can access it by glance via standard api, and nova can<br>
prepare the R/W image (base on R/O volume) for the instance normally.<br>
<br>
And more, I consider the R/O volume support and cinder driver for<br>
glance is valuable because on nova side we can give some code changes<br>
to allow nova prepare instance disk via particular COW mechanism base<br>
on particular cinder backend store capability with more efficiency<br>
way, such as efficient snapshot.<br>
<br>
Thanks,<br>
Zhi Yan<br>
<br>
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<a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><o:p></o:p></p>
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