Re:Live Migrating QEMU-KVM Virtual Machines
by chousuke on Tuesday March 24, 2015 @03:06PM
(#9258722)
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.
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...