Am 24.08.2010 14:27, schrieb Avi Kivity: > On 08/24/2010 03:21 PM, Alexander Graf wrote: >> Avi Kivity wrote: >>> On 08/24/2010 03:12 PM, Alexander Graf wrote: >>>>> Well, safety is not boolean. Considering to make it mostly safe instead >>>>> of completely safe because of the performance doesn't mean that we >>>>> should make it completely unsafe. >>>>> >>>> What is safety then? A vague feeling of "oh today is monday so my data >>>> is safe, but on tuesday I always lose my image data"? Either we promise >>>> to keep data safe or we don't. There is no in between. >>>> >>> Do you drive a car? >> Would you buy a car where the breaks are known to not always work? ;) > > That's not the case, even with cache=unsafe. > >>> Though in general I agree we shouldn't compromise on data integrity. >> That's my point. Either we go for it or we don't. > > I don't know how bad the performance regression is, and how large the > integrity risk is. I'd default towards preserving integrity, but maybe > this situation is different.
I have reports of installations taking like 50 min instead of 14 min. My own qemu-io based test goes up from 1 s to 23 s. And I think the winner is Michael's image conversion which went up from 30 s to 49 min. So it's not like we're talking about just some 10 or 20 percent. Kevin
