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<p class="MsoNormal"><span lang="EN-US">Hi Duncan,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Really thanks for replying and sorry for my delayed response due to Chinese new year.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><i><span lang="EN-US">> 1) Driver authors tend, in my experience, to know more than admins, so<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span lang="EN-US">> drivers should be able (where useful) to be able to set a default value to<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span lang="EN-US">> either filter expression or weighting expression<o:p></o:p></span></i></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Actually I am in a team which is writing cinder driver for Huawei storage array, and I agree that driver authors know more than admins about the storage device, but not the requirement. I think it’s admin’s choice what
kind of storage is needed, e.g:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">1) Admin A cares nothing but free capacity, so capacity filter is enough for him;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">2) Admin B want SLA volume, so he need min_iops/min_bandwidth/replication to be filter conditions (in this case, the admin is likely to create a special volume-type);<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I’m not sure if the scenario above is in the scope of this BP, but I think editing equation in cinder.conf IS a way to match the requirement.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><i><span lang="EN-US">> 2) Admins definitely need to be able to over-ride this if desired via<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span lang="EN-US">> cinder.conf<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span lang="EN-US"><o:p> </o:p></span></i></p>
<p class="MsoNormal"><i><span lang="EN-US">> I thing it is fairly easy (and beneficial) to go through the in-tree<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span lang="EN-US">> drivers and add the conf value to the stats report, once the base driver<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span lang="EN-US">> change has merged.<o:p></o:p></span></i></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Do you mean the cinder base driver can have the built-in implementation of filter/goodness function? Is there a plan? maybe we can do something about this. <o:p></o:p></span></p>
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