Many ways to store data devices distnb Reliability in real world (CERN) 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 10GB files,that's one file corrupted per 1000 files written too HSM 7/42 S.Ponce-CERNMany ways to store data 7 / 42 S. Ponce - CERN devices distrib // c/c zoo HSM Reliability in real world (CERN) 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 10GB files, that’s one file corrupted per 1000 files written 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 10 19 bits read/written for 10GB files, that’s one file corrupted per 100M files written