[pve-devel] Default cache mode for VM hard drives

[Dietmar Maurer]

> If you provide a buffer to the kernel, that you change while it is 
> working with it, I don't know why you expect a reliable/predictable 
> result? Specially (but not only) if you tell it not to make a copy!!
> 
> Note that without O_DIRECT you won't get a "correct" result either; disk 
> may end not containing the data in the buffer when write was called. 
> Softmirror data will be identically uncertain :)

Again, we do not expect a correct, reliable or predicable result. But we
would expect that the RAID device is still in a consistent state. Or 
is that too much to expect?