<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"><base href="x-msg://1594/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I believe it was my comment on the review that started this idea, but I was actually suggesting something different from point 2 below. Comments in line.<div><div><div>On Feb 4, 2013, at 3:33 AM, "Kanade, Rohan" <<a href="mailto:Rohan.Kanade@nttdata.com">Rohan.Kanade@nttdata.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Menlo; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">This is in context to an ongoing review<span class="Apple-converted-space"> </span><a href="https://review.openstack.org/#/c/20333/" style="color: purple; text-decoration: underline; ">https://review.openstack.org/#/c/20333/</a> and comments on the review.<o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">There are two cases which need to be considered for the topic of “Attached and Un-attached Volume migration”.<o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Case 1: Is intended to be implemented by the above review . Libvirt api (migrateToURI) takes care of correctly copying and syncing data between the original volumes (attached) on “cinder-node1” and the new destination volumes on "cinder-node2", without taking the original volumes offline or detaching them before copying.</div></div></div></blockquote><div><br></div><div>I may have slightly misunderstood the functionality of the patch, so let me ask the following question to clarify:</div><div><br></div><div>Is it possible to do live-migration and specify the same compute node so that only the volumes are migrated?</div><div><br></div><div>for example:</div><div><br></div><div>nova live-migration instance1 compute-node1 --block_device_mapping …</div><div><br></div><div>If it is possible to keep the instance on the same node while migrating volumes, then I think my concerns are addressed.</div><br><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Menlo; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Case 2: Adding a separate command to migrate individual volumes that are un-attached could be useful in the following scenario:</div></div></div></blockquote><div><br></div>I agree that this is important and could be done in a separate patch.</div><div><br><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Menlo; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">"cinder-node1" contains 10 volumes , 2 volumes are attached to "instance1" on "compute-node1", To take down "cinder-node1", we can block migrate the "instance1" using this patch, which will migrate the 2 volumes to "cinder-node2", But the rest 8 volumes on "cinder-node1" need to be migrated too. Since taking down "cinder-node1" will render the remaining 8 volumes unusable. This is where individual volume migration can be used.<o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">But , for all volumes on "cinder-node1" which are attached to "instance1", they cannot be simply live migrated individually or detached and then migrated.<o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">There are two points to be observed here:<o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">1) We cannot use LVM volume snapshots and recreate another volume on the new "cinder-node2", since LVM commands are specific to<o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">the node.<o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">2) We can use rsync to copy/sync between the original volume on "cinder-node1" and the destination volume on "cinder-node2".</div></div></div></blockquote><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Menlo; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p></o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">3) The volume uuid will change, since we are creating a destination volume in which the source volume data will be copied, This might cause issue to users who are using the source volume uuid's in automated scripts etc.</div></div></div></blockquote><div><br></div>I think it would be fairly easy to come up with a way of copying volumes without having to change the uuid<br><blockquote type="cite"><div lang="EN-US" link="blue" vlink="purple" style="font-family: Menlo; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p></o:p></div></div><br clear="both">______________________________________________________________________<br>Disclaimer:This email and any attachments are sent in strictest confidence for the sole use of the addressee and may contain legally privileged, confidential, and proprietary data. 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