{"type":"excalidraw","version":2,"source":"https://AwesomeSystemDesign.dev","elements":[{"angle":0,"strokeColor":"#6577aa","backgroundColor":"#eef1fc","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-1"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-1"}],"updated":0,"link":null,"locked":false,"id":"shape-0","type":"rectangle","seed":41,"x":16,"y":16,"width":288,"height":93.2,"customData":{"revealStep":1}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-1"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-1","type":"text","seed":114,"x":36,"y":34,"width":248,"height":57.2,"fontSize":22,"fontFamily":1,"text":"Annual Durability\nCalculation","originalText":"Annual Durability\nCalculation","textAlign":"left","verticalAlign":"middle","containerId":"shape-0","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":1}},{"angle":0,"strokeColor":"#628572","backgroundColor":"#edf5ee","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-2"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-3"}],"updated":0,"link":null,"locked":false,"id":"shape-2","type":"rectangle","seed":187,"x":16,"y":153.2,"width":288,"height":379.2,"customData":{"revealStep":2}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-2"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-3","type":"text","seed":260,"x":36,"y":171.2,"width":248,"height":343.2,"fontSize":22,"fontFamily":1,"text":"Assumptions:\n• Disk Annual Failure\nRate (AFR) = 2%\n• Replication factor\n= 3 (across 3 AZs)\n• Mean Time To\nRepair (MTTR) = 4\nhours\n• Chunks per disk =\n3,000 (64 MB\nchunks on 200 TB\ndisk)","originalText":"Assumptions:\n• Disk Annual Failure\nRate (AFR) = 2%\n• Replication factor\n= 3 (across 3 AZs)\n• Mean Time To\nRepair (MTTR) = 4\nhours\n• Chunks per disk =\n3,000 (64 MB\nchunks on 200 TB\ndisk)","textAlign":"left","verticalAlign":"middle","containerId":"shape-2","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":2}},{"angle":0,"strokeColor":"#a68a53","backgroundColor":"#fff7e6","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-3"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-5"}],"updated":0,"link":null,"locked":false,"id":"shape-4","type":"rectangle","seed":333,"x":16,"y":576.4,"width":288,"height":93.2,"customData":{"revealStep":3}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-3"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-5","type":"text","seed":406,"x":36,"y":594.4,"width":248,"height":57.2,"fontSize":22,"fontFamily":1,"text":"P(single disk fails in\na year) = 0.02","originalText":"P(single disk fails in\na year) = 0.02","textAlign":"left","verticalAlign":"middle","containerId":"shape-4","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":3}},{"angle":0,"strokeColor":"#9180ac","backgroundColor":"#f4effb","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-4"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-7"}],"updated":0,"link":null,"locked":false,"id":"shape-6","type":"rectangle","seed":479,"x":16,"y":713.6,"width":288,"height":179,"customData":{"revealStep":4}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-4"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-7","type":"text","seed":552,"x":36,"y":731.6,"width":248,"height":143,"fontSize":22,"fontFamily":1,"text":"P(2nd replica disk\nfails during 4-hour\nrepair window):\n= 0.02 × (4 / 8760)\n= 9.13 × 10⁻⁶","originalText":"P(2nd replica disk\nfails during 4-hour\nrepair window):\n= 0.02 × (4 / 8760)\n= 9.13 × 10⁻⁶","textAlign":"left","verticalAlign":"middle","containerId":"shape-6","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":4}},{"angle":0,"strokeColor":"#6577aa","backgroundColor":"#eef1fc","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-5"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-9"}],"updated":0,"link":null,"locked":false,"id":"shape-8","type":"rectangle","seed":625,"x":16,"y":936.6,"width":288,"height":179,"customData":{"revealStep":5}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-5"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-9","type":"text","seed":698,"x":36,"y":954.6,"width":248,"height":143,"fontSize":22,"fontFamily":1,"text":"P(3rd replica disk\nalso fails in same 4\nhours):\n= 9.13 × 10⁻⁶ × (4 /\n8760) = 4.17 × 10⁻⁹","originalText":"P(3rd replica disk\nalso fails in same 4\nhours):\n= 9.13 × 10⁻⁶ × (4 /\n8760) = 4.17 × 10⁻⁹","textAlign":"left","verticalAlign":"middle","containerId":"shape-8","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":5}},{"angle":0,"strokeColor":"#628572","backgroundColor":"#edf5ee","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-6"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-11"}],"updated":0,"link":null,"locked":false,"id":"shape-10","type":"rectangle","seed":771,"x":16,"y":1159.6,"width":288,"height":121.8,"customData":{"revealStep":6}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-6"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-11","type":"text","seed":844,"x":36,"y":1177.6,"width":248,"height":85.8,"fontSize":22,"fontFamily":1,"text":"P(losing one specific\nchunk in a year):\n≈ 4.17 × 10⁻⁹ per chunk","originalText":"P(losing one specific\nchunk in a year):\n≈ 4.17 × 10⁻⁹ per chunk","textAlign":"left","verticalAlign":"middle","containerId":"shape-10","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":6}},{"angle":0,"strokeColor":"#a68a53","backgroundColor":"#fff7e6","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-7"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-13"}],"updated":0,"link":null,"locked":false,"id":"shape-12","type":"rectangle","seed":917,"x":16,"y":1325.3999999999999,"width":288,"height":207.6,"customData":{"revealStep":7}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-7"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-13","type":"text","seed":990,"x":36,"y":1343.3999999999999,"width":248,"height":171.6,"fontSize":22,"fontFamily":1,"text":"For 100 trillion\nchunks:\nExpected chunks lost\n= 100T × 4.17 × 10⁻⁹ ≈\n417,000\n... that's too many!","originalText":"For 100 trillion\nchunks:\nExpected chunks lost\n= 100T × 4.17 × 10⁻⁹ ≈\n417,000\n... that's too many!","textAlign":"left","verticalAlign":"middle","containerId":"shape-12","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":7}},{"angle":0,"strokeColor":"#9180ac","backgroundColor":"#f4effb","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-8"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-15"}],"updated":0,"link":null,"locked":false,"id":"shape-14","type":"rectangle","seed":1063,"x":16,"y":1576.9999999999998,"width":288,"height":379.2,"customData":{"revealStep":8}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-8"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-15","type":"text","seed":1136,"x":36,"y":1594.9999999999998,"width":248,"height":343.2,"fontSize":22,"fontFamily":1,"text":"Solution: Faster\nrepair + more\nreplicas for critical\ndata\nWith MTTR = 1 hour\nand awareness-based\nplacement:\nP(data loss per\nchunk) ≈ 10⁻¹²\nExpected losses at\n100T chunks = 0.1\nper year ✅","originalText":"Solution: Faster\nrepair + more\nreplicas for critical\ndata\nWith MTTR = 1 hour\nand awareness-based\nplacement:\nP(data loss per\nchunk) ≈ 10⁻¹²\nExpected losses at\n100T chunks = 0.1\nper year ✅","textAlign":"left","verticalAlign":"middle","containerId":"shape-14","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":8}},{"angle":0,"strokeColor":"#6577aa","backgroundColor":"#eef1fc","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-9"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-17"}],"updated":0,"link":null,"locked":false,"id":"shape-16","type":"rectangle","seed":1209,"x":16,"y":2000.1999999999998,"width":288,"height":436.40000000000003,"customData":{"revealStep":9}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-9"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-17","type":"text","seed":1282,"x":36,"y":2018.1999999999998,"width":248,"height":400.40000000000003,"fontSize":22,"fontFamily":1,"text":"Additional measures:\n• Rack-aware\nplacement (replicas\non different racks)\n• Correlated failure\ndetection (if disk A\nfails, proactively\nadd extra replicas\nfor chunks that\nshare a node with\ndisk A)\n• Scrubbing detects\nbit rot before it's\nneeded for repair","originalText":"Additional measures:\n• Rack-aware\nplacement (replicas\non different racks)\n• Correlated failure\ndetection (if disk A\nfails, proactively\nadd extra replicas\nfor chunks that\nshare a node with\ndisk A)\n• Scrubbing detects\nbit rot before it's\nneeded for repair","textAlign":"left","verticalAlign":"middle","containerId":"shape-16","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":9}}],"appState":{"viewBackgroundColor":"#fbfbf8","gridSize":null},"files":{}}