{
  "slug": "maid",
  "term": "Massive array of idle disks",
  "aliases": [
    "MAID",
    "massive arrays of idle disks"
  ],
  "definition": "A massive array of idle disks is a storage architecture that keeps selected disks spun down between accesses to reduce energy use.",
  "note": "Placement, idle timers and caching determine which drives must wake for a request [maid-paper]. A nearline HDD product class does not imply this power policy [ibm].",
  "provenance": [
    "Colarelli and Grunwald (2002) evaluated trace-driven simulation, not a production energy survey. [maid-paper]"
  ],
  "status": "research",
  "advantages": [],
  "limitations": [],
  "related": [
    "nearline-hdd",
    "power-aware-coding",
    "cold-archive",
    "erasure-coding"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-17",
  "citations": [
    {
      "id": "maid-paper",
      "title": "Colarelli and Grunwald: Massive Arrays of Idle Disks For Storage Archives (SC 2002), sections 2-5.",
      "url": "https://www3.cs.stonybrook.edu/~anshul/courses/cse591_s16/maid.pdf",
      "accessed": "2026-10-17"
    },
    {
      "id": "ibm",
      "title": "IBM technical blog: The Correct Use of the term Nearline.",
      "url": "https://www.ibm.com/support/pages/correct-use-term-nearline",
      "accessed": "2026-10-17"
    }
  ]
}