On 06/05/2012 10:38 PM, MORITA Kazutaka wrote: > The below change to the qemu block driver would fix the problem. > I think this kind of ordering should be done in the gateway node, > though. This will dramatically hurt the IO performance, at least for object cache, I can see concurrent access to the same object, but NOT overlapped at all. Most of disk driver default to 512K for maximum IO size, this means most of chances we will get requests(split by OS driver and block layer) to access the same 4M object. I suggest to consider the fix if the problem is really emerging with more information. We shouldn't fix the imaginary problem, especially compromise the performance a lot. Thanks, Yuan |