Yanyg - Software Engineer

Cold Storage System

目录

1 Microsoft Pelican Cold Storage System

1.1 Introduction

  • 52U standard RACK, 1152 HDD;
  • 6x8U chassis(JBOD), 12 trays, 192 HDD per chassis;
    • RACK Topology: 6x12x16; microsoft-pelican-rack-topo.png
    • Tray has independent power domain;
  • Throughput 1GBps per PB so retrieve cycle is 13 days;

1.2 Software stack

1.2.1 data layout

  • split to a sequence of 128KB data fragments;
  • k data fragments generate r additional fragments from EC;
  • Refer k+r data fragments as a stripe;
  • Store a stripe to k+r disks;
  • k=15, r=3, overhead=0.2
  • cooling domain, power group microsoft-pelican-colliding-groups.png
  • io scheduler Reordering, Rate limiting;
  • config
    • 48 groups, each 24 disks;
  • Metrics
    • Completion Time
    • Time to first byte
    • Service Time
    • Average reject rate
    • Throughput

2 Facebook Cold Storage System

  • Architecture fb-cold-storage-architecture.png
  • power group, like as microsoft Pelican;
    • Diff from Pelican: One node one disk, many node, predefined power cycle;
  • 10+4, overhead=0.4

fb-cold-storage-ec.png

  • Metadata

3 References