Found out that the I/O errors can be triggerd by network traffic.
I was able to kill a dd by pingflooding the machine remotly :-) This also explains why my dd script had not triggerd errors, but copying arenas and vacing from remote machine did. I guess this is interrupt load dependend. I changed sdata.c to: return SDretry if starting dmarequest fails, return SDretry and reseting controller if dma times out, return SDretry on request is done and error signaled, and added a counter that resets the controller if a request was 1000 times retried... The machine ran the whole night with bodth drives in DMA and heavy load. vacing, pingflooded from outside, ddtest on both drives and still alive! :-) futher testing this weekend... cinap
