Re: [Qemu-discuss] qcow2 performanceimprove

[yang.bin18]

>>>If there is no backing file or snapshot you still need to fill the>>>cluster 
>>>with zeroes, and that's going to be slower with larger>>>clusters.>>>>     
>>>If not fill zeroes and only write guest data ,what`s wrong could>>     
>>>happen ?>The following could happen:> 1) Guest reads at offset  [0,   4k] -> 
>>>there's only zeroes> 2) Guest writes at offset [8k, 16k]> 3) Guest reads at 
>>>offset  [0,   4k] -> there's something else now>Berto






   Why  could guest read the area  at offset [0, 4k] has not be writen yet ?


   Yang.bin