Preserving data risks consistency Risks for my data -Hardware some numbers for disks probability of losing a disk per year:few %up to 10% with 60K disks,it's around 10 per day 。and all files are lost o one unrecoverable bit error in 1014 bits read/written for 1GB files,that's one file corrupted per 10K files written some numbers for tapes probability of losing a tape per year:10-4 and you recover most of the data on it o net result is 10-7 file loss per year one unrecoverable bit error in 1019 bits read/written for 1GB files,that's one file corrupted per 1G files written 5/43 S.Ponce-CERNPreserving data 5 / 43 S. Ponce - CERN risks consistency safety c/c Risks for my data - Hardware some numbers for disks probability of losing a disk per year : few %, up to 10% with 60K disks, it’s around 10 per day and all files are lost one unrecoverable bit error in 1014 bits read/written for 1GB files, that’s one file corrupted per 10K files written some numbers for tapes probability of losing a tape per year : 10−4 and you recover most of the data on it net result is 10−7 file loss per year one unrecoverable bit error in 1019 bits read/written for 1GB files, that’s one file corrupted per 1G files written