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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">ZFS feature flags are different on two important fronts.<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">First, they are binary. There is an intrinsic limit to the number claimable and no reason not to think that two project would not claim the same binary value.<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">More importantly, ZFS has a very specific challenge caused by Oracle maintaining their own closed source repository. There is a specific challenge in trying<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">To import a file system created under a closed repository to a file system built on the open repository (or vise versa).<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">Maybe I’m missing something, but where is the scenario for an openstack deployment that is built from mixed repositories?<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Justin Santa Barbara [mailto:justin@fathomdb.com]
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<b>Sent:</b> Friday, April 13, 2012 4:40 PM<br>
<b>To:</b> Caitlin Bestler<br>
<b>Cc:</b> Jorge Williams; Mark Nottingham; Thierry Carrez; <openstack@lists.launchpad.net><br>
<b>Subject:</b> Re: [Openstack] Just JSON, and extensibility<o:p></o:p></span></p>
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<p class="MsoNormal">It's easy when each new version is defined by a central body.<o:p></o:p></p>
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<p class="MsoNormal">The problem we face is that we want to allow HP, Rackspace, Nexenta etc to define their own extensions, without serializing through a central body. Some extensions may only apply to private clouds and never be shared publicly.<o:p></o:p></p>
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<p class="MsoNormal">This is a bit like ZFS feature flags, to use an example that should be near and dear to your heart!<o:p></o:p></p>
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<p class="MsoNormal">On Fri, Apr 13, 2012 at 2:24 PM, Caitlin Bestler <<a href="mailto:Caitlin.Bestler@nexenta.com">Caitlin.Bestler@nexenta.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Exactly what do you see as the required “non-linear extensibility”?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">These are ultimately requests to a server. Each new extension is coded in that server.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">There is no value in a client making up its own extensions that are not understood by the server.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">What is relevant is a server continuing to support clients that have not yet been updated to<br>
understand a new format.</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">As I stated in my first post, that problem was solved in ANSI C. Python/JSON is trivial.</span><o:p></o:p></p>
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