In qemu 0.14 cache=writeback and cache=none are expected to perform
well. The default cache=writethrough is a very conservative setting
which is slow by design. I'm pretty sure that it has always been slow,
even before 0.12.5.
I think that the specific problem with savevm may be related to the VM
** Description changed:
==
- Impact: occasional qcow2 corruption
+ Impact: occasional image corruption (any format on local filesystem)
Test case: see the qemu-img command below
Regression potential: this cherrypicks a patch from
