<div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">Hi,</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">When you'll press 'ok', a
snapshot of that disk's image chain (its Base volume) is created in the source storage
domain, and the entire image chain is replicated in the destination
storage domain.</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">It doesn't effect the original disk, and meanwhile, the VM keep "act normally":</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small"> - If the VM's actions only deal with reading the disk, creating its snapshot should be a simpler task.<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">- In case the VM writes data to the disk, a new snapshot volume which contains only the changes (for simplifying, you can think the way "git diff" works) is being created on both source and destination targets.</div><div style="font-family:tahoma,sans-serif;font-size:small" class="gmail_default">While the base volume is being copied from the source target to the destination target, those snapshot volumes (for disk's changes) get synchronized.</div><div style="font-family:tahoma,sans-serif;font-size:small" class="gmail_default"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">When the disk's images on both source and destination targets are identical, the VM points to the 'new' image and deletes the old pointer. <br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">I.e. the disk was successfully moved.</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">In case of any failure during the migration, since targeted destination contains only a snapshot of the original disk's image, the original image isn't being effected,</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">So there won't be a data lose and operation just fails.</div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small">Also, busy network can affect the migration's duration. <br></div><div class="gmail_default" style="font-family:tahoma,sans-serif;font-size:small"><br></div><div class="gmail_extra"><div style="font-family:tahoma,sans-serif;font-size:small" class="gmail_default">More data about the process are available here: <a href="https://www.ovirt.org/develop/release-management/features/storage/storagelivemigration/">https://www.ovirt.org/develop/release-management/features/storage/storagelivemigration/</a></div><br clear="all"><div><div class="gmail-m_1873819132422419795gmail-m_-2870035305741612318gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><span style="font-family:tahoma,sans-serif"><b>Regards,<br></b></span></div><span style="font-family:tahoma,sans-serif"><b>Shani Leviim<br></b></span></div></div></div></div></div>
<br><div class="gmail_quote">On Sun, Nov 26, 2017 at 5:38 PM, Arman Khalatyan <span dir="ltr"><<a href="mailto:arm2arm@gmail.com" target="_blank">arm2arm@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">hi Sahni,<div dir="auto">thanks for the details.</div><div dir="auto">Looks like the live storage migration might fail on the heavy loaded virtual machines. I just tried to move from nfs to iscsi storage(most of the cases they moved w/o error), the message on the move dialog warns us "! moving following disks when VM is running", <span style="font-family:sans-serif">if we press "ok ! do it" </span>what are the consequences? it is not explained in the docs. </div>thank you beforehand<div dir="auto"><span class="gmail-m_1873819132422419795gmail-m_-2870035305741612318HOEnZb"><font color="#888888">Arman.</font></span><div><div class="gmail-m_1873819132422419795gmail-m_-2870035305741612318h5"><br><div class="gmail_extra" dir="auto"><br><div class="gmail_quote">Am 26.11.2017 2:12 nachm. schrieb "Shani Leviim" <<a href="mailto:sleviim@redhat.com" target="_blank">sleviim@redhat.com</a>>:<br type="attribution"><blockquote class="gmail-m_1873819132422419795gmail-m_-2870035305741612318m_1445926229849984623quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div style="font-family:tahoma,sans-serif;font-size:small">Hi Arman,</div><div style="font-family:tahoma,sans-serif;font-size:small">VM's migration and disks migration are two different things:</div><div style="font-family:tahoma,sans-serif;font-size:small"><br></div><div style="font-family:tahoma,sans-serif;font-size:small">- Live storage migration:</div><div style="font-family:tahoma,sans-serif;font-size:small">A VM's disk can be moved to another storage domain while the VM is running, by copying the disk's structure the destination domain.<br>The hard part of live storage migration is moving the active layer
volumes from one domain to another, while the VM is writing to those
volumes.</div><div style="font-family:tahoma,sans-serif;font-size:small">By using a replication operation, the data is written to both source and destination volumes. <br>When both volumes contain the same
data, the block job operation can be aborted, pivoting to the new disk.</div><div style="font-family:tahoma,sans-serif;font-size:small"><br></div><div style="font-family:tahoma,sans-serif;font-size:small">You may find more detailed information here:
<a href="https://www.ovirt.org/develop/release-management/features/storage/live-storage-migration-between-mixed-domains/" target="_blank">https://www.ovirt.org/develop/<wbr>release-management/features/st<wbr>orage/live-storage-migration-b<wbr>etween-mixed-domains/</a></div><div style="font-family:tahoma,sans-serif;font-size:small"><br></div><div style="font-family:tahoma,sans-serif;font-size:small">- Live migration:</div><div style="font-family:tahoma,sans-serif;font-size:small">Provides the ability to move a running virtual machine between physical
hosts with no interruption to service.</div><div style="font-family:tahoma,sans-serif;font-size:small">The virtual machine remains
powered on and user applications continue to run while the virtual
machine is relocated to a new physical host.</div><div style="font-family:tahoma,sans-serif;font-size:small">A running virtual machine can be live migrated to any host within its
designated host cluster.</div><div style="font-family:tahoma,sans-serif;font-size:small">Live migration of virtual machines does not
cause any service interruption.</div><div style="font-family:tahoma,sans-serif;font-size:small"><br></div><div style="font-family:tahoma,sans-serif;font-size:small">You may find some more information here: <a href="https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.5/html/Administration_Guide/sect-Migrating_Virtual_Machines_Between_Hosts.html#What_is_live_migration" target="_blank">https://access.redhat.com/docu<wbr>mentation/en-US/Red_Hat_Enterp<wbr>rise_Virtualization/3.5/html/A<wbr>dministration_Guide/sect-Migra<wbr>ting_Virtual_Machines_Between_<wbr>Hosts.html#What_is_live_migrat<wbr>ion</a></div><div style="font-family:tahoma,sans-serif;font-size:small"><br></div><div style="font-family:tahoma,sans-serif;font-size:small">Hope it helps!<br></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail-m_1873819132422419795gmail-m_-2870035305741612318m_1445926229849984623m_4892094212054720622gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><span style="font-family:tahoma,sans-serif"><b>Regards,<br></b></span></div><span style="font-family:tahoma,sans-serif"><b>Shani Leviim<br></b></span></div></div></div></div></div>
<br><div class="gmail_quote"><div class="gmail-m_1873819132422419795gmail-m_-2870035305741612318m_1445926229849984623quoted-text">On Fri, Nov 24, 2017 at 11:54 AM, Arman Khalatyan <span dir="ltr"><<a href="mailto:arm2arm@gmail.com" target="_blank">arm2arm@gmail.com</a>></span> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="gmail-m_1873819132422419795gmail-m_-2870035305741612318m_1445926229849984623elided-text">hi,<br>
I have some test enviroment with ovirt<br>
"4.2.0-0.0.master.201711140711<wbr>05.gitdfdc401.el7.centos"<br>
2hosts+2NFS-domains<br>
<br>
During the multiple disk movement between the domains I am getting this warning:<br>
Moving disks while the VMs are running.(this is not so scary red as in<br>
4.1.x :) )<br>
<br>
What kind of problems can happen during the movement?<br>
<br>
Thanks,<br>
Arman.<br></div><div class="gmail-m_1873819132422419795gmail-m_-2870035305741612318m_1445926229849984623quoted-text">
______________________________<wbr>_________________<br>
Users mailing list<br>
<a href="mailto:Users@ovirt.org" target="_blank">Users@ovirt.org</a><br>
<a href="http://lists.ovirt.org/mailman/listinfo/users" rel="noreferrer" target="_blank">http://lists.ovirt.org/mailman<wbr>/listinfo/users</a><br>
</div></blockquote></div><br></div>
</blockquote></div><br></div></div></div></div></div>
</blockquote></div><br></div></div>