Preserving data risks consistency Risks for my data -Software BUGS o in your software oe.g.scheduling twice a transfer,not receiving data on the second run and overwriting the correct file with an empty one o in your dependencies .e.g.the transfer protocol used does not support checksum and data may be corrupted by TCP(checksum is only 16 bit,one corrupted packet in 65536 will go through) o in the OS or common libraries e.g.libc locks not being atomic o in the hardware-that is in the micro code running inside e.g.RAID controllers o in your admin tools o e.g.recycling a tape that was not empty 6/43 S.Ponce-CERNPreserving data 6 / 43 S. Ponce - CERN risks consistency safety c/c Risks for my data - Software BUGS ! in your software e.g. scheduling twice a transfer, not receiving data on the second run and overwriting the correct file with an empty one in your dependencies e.g. the transfer protocol used does not support checksum and data may be corrupted by TCP (checksum is only 16 bit, one corrupted packet in 65536 will go through) in the OS or common libraries e.g. libc locks not being atomic in the hardware - that is in the micro code running inside e.g. RAID controllers in your admin tools e.g. recycling a tape that was not empty