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<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">Hi, Brent<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">The following are mechanism of Cinder volume cache.<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><o:p> </o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">Creation of cached volume:
<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">It creates a cached volume in the backend storage when creating from an image.<o:p></o:p></span></p>
<p style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt;text-indent:-.25in;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">Create_from_image:
<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><a href="https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L890">https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L890</a><o:p></o:p></span></p>
<p style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt;text-indent:-.25in;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">Return image cache entry: If not existed, it creates a new entry.<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><a href="https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L746">https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L746</a><o:p></o:p></span></p>
<p style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:0in;margin-left:.5in;margin-bottom:.0001pt;text-indent:-.25in;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">Create a new image-volume and cache entry for it:<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><a href="https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L872">https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L872</a><o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black">Use a cached volume when creating a volume:<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><a href="https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L723-L735">https://github.com/openstack/cinder/blob/stable/pike/cinder/volume/flows/manager/create_volume.py#L723-L735</a>
<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"> Delete the cache volume: When capacity and number of cache entries exceed specified limit, it deletes cache entries (cached volumes).
<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:black"><a href="https://github.com/openstack/cinder/blob/stable/pike/cinder/image/cache.py#L164">https://github.com/openstack/cinder/blob/stable/pike/cinder/image/cache.py#L164</a>
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Best wishes<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Lisa<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><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"> Rowsell, Brent [mailto:Brent.Rowsell@windriver.com]
<br>
<b>Sent:</b> Thursday, September 6, 2018 10:02 AM<br>
<b>To:</b> Li, Xiaoyan <xiaoyan.li@intel.com>; starlingx-discuss@lists.starlingx.io<br>
<b>Subject:</b> RE: [Starlingx-discuss] [StarlingX] Use Cinder generic image cache to replace raw caching<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">We would need to review this feature to ensure it provides equivalent functionality first.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">If it does, great, we can look at reverting and enabling this cinder functionality.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Brent
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><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"> Li, Xiaoyan [<a href="mailto:xiaoyan.li@intel.com">mailto:xiaoyan.li@intel.com</a>]
<br>
<b>Sent:</b> Wednesday, September 5, 2018 9:59 PM<br>
<b>To:</b> <a href="mailto:starlingx-discuss@lists.starlingx.io">starlingx-discuss@lists.starlingx.io</a><br>
<b>Subject:</b> [Starlingx-discuss] [StarlingX] Use Cinder generic image cache to replace raw caching<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hi all,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">This email is about Raw caching function in StarlingX. This feature is to cache an image in backend storage like Ceph when we first create a volume in this backend storage.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">In fact, Cinder upstream has already had a similar function in Pike release.
<a href="https://specs.openstack.org/openstack/cinder-specs/specs/liberty/image-volume-cache.html">
<span style="color:#0563C1">https://specs.openstack.org/openstack/cinder-specs/specs/liberty/image-volume-cache.html</span></a>
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">So I want to revert Raw caching function in StarlingX, and use Cinder generic image cache instead.
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">The problem is that we need to update Cinder config in StarlingX. Any comments?
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Best wishes<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Lisa<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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