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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">The terms do vary significantly between different vendors which adds to the confusion. I’ll try to add what we see from a CERN perspective
(which is not always your typical customer profile but we use ceph and NetApp). I assume this would still follow the approach where the storage subsystem is in charge and cinder issues the commands to set things up.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Replication for us would mean copy of a volume to a remote location. Parameterisation such as copy type (async/sync), maximum delay
and target pool would be expected.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Consistency groups for me would be how to handle multiple volume replication in terms of sync points to ensure a consistent set of
volumes. Allowing a disaster recovery scenario is our most obvious use case, i.e. restart application VMs remotely.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">We have use cases for replication (such as online database logs), less for consistency groups but as we move more into VMs with external
system disk/data disk models where we’d like the two to be in sync if possible.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">What are the specific questions that you have in mind ?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US">Tim<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""> John Griffith [mailto:john.griffith@solidfire.com]
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<b>Sent:</b> 26 July 2014 16:29<br>
<b>To:</b> openstack-operators@lists.openstack.org<br>
<b>Subject:</b> [Openstack-operators] [OpenStack-Operators] [Cinder] Request for input on new/advanced features<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">1. Replication<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">2. Consistency Groups<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">It's easy for Vendors to come to me and say "we have lots of customers asking for this" but personally I'd love to get feedback directly from the actual customers, that's where you all come in.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">So, if any of you out there are interested in these topics from a Cinder perspective I'd love to hear from you. If there's interest we can either start an ML thread to discuss, or perhaps a meeting
to catch everybody up and hash things out a bit. I'd like to discuss the current proposals and go through what you as Operators may feel should be priorities (or better yet things you don't care about). I make no promises on the outcome of this little experiment
but thought it would be interesting to try and get user input up front before we release new features.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">Let me know your thoughts, I'll avoid a bunch of detail in this posting until I get a feel for who if anybody is interested in helping out.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">Thanks,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">John<o:p></o:p></span></p>
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