<div dir="ltr">So the way I see it, the value here is a generic driver that can work with any storage. The downsides:<div>1. The admin has to manually provision a very big volume and attach it to the Nova and Cinder hosts. Every time a host is rebooted, or introduced, the admin must do manual work. This is one of the things OpenStack should be trying to avoid. This can't be automated without a driver, which is what you're trying to avoid.</div>
<div class="gmail_extra">2. You lose on performance to volumes by adding another layer in the stack.</div><div class="gmail_extra">3. You lose performance with snapshots - appliances will almost certainly have more efficient snapshots than LVM over network (consider that for every COW operation, you are reading synchronously over the network).</div>
<div class="gmail_extra"><br></div><div class="gmail_extra">(Basically, you turned your fully-capable storage appliance into a dumb JBOD)</div><div class="gmail_extra"><br></div><div class="gmail_extra">In short, I think the cons outweigh the pros. Are there people deploying OpenStack who would deploy their storage like this?</div>
<div class="gmail_extra"><br></div><div class="gmail_extra">Thanks,<br>Avishay<br><br><div class="gmail_quote">On Tue, May 20, 2014 at 6:31 PM, Mitsuhiro Tanino <span dir="ltr"><<a href="mailto:mitsuhiro.tanino@hds.com" target="_blank">mitsuhiro.tanino@hds.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal">Hello All,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I’m proposing a feature of LVM driver to support LVM on a shared LU.<span><u></u><u></u></span></p>
<p class="MsoNormal"><span>The proposed LVM volume driver provides these
</span>benefits<span>.</span><br>
<span> </span>- <span>
R</span>educe hardware based storage workload by offloading the workload to software based volume operation.<br>
<span> </span>- Provide quicker volume creation and snapshot creation without storage workloads.<br>
<span> </span>- Enable cinder to any kinds of shared storage volumes without specific cinder storage<span>
</span>driver.<span><u></u><u></u></span></p>
<p class="MsoNormal"><span> </span>-<span> Better I/O performance using direct volume access via Fibre channel.<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal">In the attachment pdf, following contents are explained.<u></u><u></u></p>
<p class="MsoNormal"> 1. Detail of Proposed LVM volume driver<u></u><u></u></p>
<p class="MsoNormal"> 1-1. Big Picture<u></u><u></u></p>
<p class="MsoNormal"> 1-2. Administrator preparation<u></u><u></u></p>
<p class="MsoNormal"> 1-3. Work flow of volume creation and attachment<u></u><u></u></p>
<p class="MsoNormal"> 2. Target of Proposed LVM volume driver<u></u><u></u></p>
<p class="MsoNormal"> 3. Comparison of Proposed LVM volume driver<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Could you review the attachment?<u></u><u></u></p>
<p class="MsoNormal">Any comments, questions<span>, additional ideas</span> would be appreciated.<span><u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal">Also there are blueprints, wiki and patches related to the slide.<u></u><u></u></p>
<p class="MsoNormal"><a href="https://blueprints.launchpad.net/cinder/+spec/lvm-driver-for-shared-storage" target="_blank">https://blueprints.launchpad.net/cinder/+spec/lvm-driver-for-shared-storage</a><u></u><u></u></p>
<p class="MsoNormal"><a href="https://blueprints.launchpad.net/nova/+spec/lvm-driver-for-shared-storage" target="_blank">https://blueprints.launchpad.net/nova/+spec/lvm-driver-for-shared-storage</a><u></u><u></u></p>
<p class="MsoNormal"><a href="https://wiki.openstack.org/wiki/Cinder/NewLVMbasedDriverForSharedStorageInCinder" target="_blank">https://wiki.openstack.org/wiki/Cinder/NewLVMbasedDriverForSharedStorageInCinder</a><u></u><u></u></p>
<p class="MsoNormal"><a href="https://review.openstack.org/#/c/92479/" target="_blank">https://review.openstack.org/#/c/92479/</a><u></u><u></u></p>
<p class="MsoNormal"><a href="https://review.openstack.org/#/c/92443/" target="_blank">https://review.openstack.org/#/c/92443/</a><u></u><u></u></p>
<p class="MsoNormal"><span style="color:black"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="color:black">Regards,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:black">Mitsuhiro Tanino <<a href="http://mitsuhiro.tanino@hds.com" target="_blank">mitsuhiro.tanino@hds.com</a>><u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:black"> <b>HITACHI DATA SYSTEMS<u></u><u></u></b></span></p>
<p class="MsoNormal"><span style="color:black"> c/o Red Hat, 314 Littleton Road, Westford, MA 01886</span><span style="color:black"><u></u><u></u></span></p>
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