On 7.8.2014 03:04, John R Pierce wrote: > On 8/6/2014 5:32 PM, Markus Falb wrote: >> Do you have barriers enabled? >> Just another shot in the dark, but 5 didn't have that. >> If you have battery backed Cache with your Controller, you can safely >> disable barriers anyway. > are you sure about this? thats not my understanding. > > What I've been told is, the battery backed write cache just lets you > enable writeback caching in the raid controller, write barriers at the > various OS layers still have to be respected, as they ensure certain > writes are completed in order. You mean there are other places besides the drive itself where I/O may be reordered? The I/O Scheduler maybe? Hmmm... -- Kind Regards, Markus Falb