Live Migrating QEMU-KVM Virtual Machines

http://developerblog.redhat.com/2015/03/24/live-migrating-qemu-kvm-virtual-machines/

by Tsiolkovsky • 11 years ago

43 5 11 years ago

developerblog.redhat.com

X-Istence• 11 years ago

I've used live migration with KVM within OpenStack and it is really damn awesome to be able to migrate all VM's from a host that needs to be downed for maintenance without causing any downtime.

Users SSH sessions may lag for a second or two, but the connection won't even get dropped.

anemic• 11 years ago

I tried this a while ago with libbirt-kvm and the most awesome thing was that I could live migrate VMs from AMD to Intel and vice versa. None of the other solutions, like vmware or xen do that, afaik.

On the not so good side is that disk cache needs to be disabled for live migration to work at all. This reduces the iops of the vm by 50-60%.

So you either get high performance or high uptime...

chousuke• 11 years ago

I think you'd generally want the host not to do write caching anyway unless you can afford to corrupt VM disks in case of host power failure.

I suppose a hardware battery-backed write cache might still be safe for live migrations.

RRRA• 11 years ago

Anyone has a solution for Live backups?

Say something that migrates the machine and initiate a shutdown as soon as it hits the other backup server?

amitshah• 11 years ago

oVirt can do this. Essentially, such policies belong to management applications, and oVirt or OpenStack are the places where you should look.

Live Migrating QEMU-KVM Virtual Machines

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