{
  "slug": "raid-01",
  "term": "RAID 01",
  "aliases": [
    "RAID 0+1",
    "RAID01",
    "RAID0+1",
    "RAID 0/1"
  ],
  "definition": "RAID 01 mirrors complete RAID 0 stripe sets, placing the redundancy layer above the striping layer.",
  "note": "RAID 0+1 reverses the nesting order of conventional RAID 1+0, which stripes over mirror groups. [swordfish-raid] In a two-side layered implementation, one failed member makes its stripe set unavailable as a complete component; the other side supplies the volume. [oracle-raid]\n\nWith stripe sets A/C and B/D, losing A and C leaves B/D intact, but losing A and D leaves neither complete side. This example assumes initially synchronized copies, readable current survivors and no rebuild. It describes component availability, not permanent destruction of every block. [hesela-raid01]\n\nAn interface can display mirrored stripe sets while software recognizes and mirrors corresponding components individually. Check the implementation and member map before inferring failure tolerance from the label. [solaris-layering]",
  "status": "shipping",
  "advantages": [],
  "limitations": [
    {
      "text": "A capacity or nesting label does not establish repair duration, controller availability or a measured failure probability.",
      "citationIds": [
        "hesela-raid01"
      ]
    }
  ],
  "related": [
    "raid",
    "raid-10",
    "mirroring",
    "striping",
    "mirror-set",
    "failure-domain"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-21",
  "citations": [
    {
      "id": "swordfish-raid",
      "title": "SNIA Swordfish 1.2.4a: RAIDType placement definitions",
      "url": "https://www.snia.org/sites/default/files/technical-work/swordfish/release/v1.2.4a/html/Specification/Swordfish_v1.2.4a_Specification.html",
      "accessed": "2026-10-21"
    },
    {
      "id": "oracle-raid",
      "title": "Oracle Linux 10: Software RAID Levels",
      "url": "https://docs.oracle.com/en/operating-systems/oracle-linux/10/stordev/stordev-SoftwareRAIDLevels.html",
      "accessed": "2026-10-21"
    },
    {
      "id": "solaris-layering",
      "title": "Solaris Volume Manager: Providing RAID-1+0 and RAID-0+1",
      "url": "https://docs.oracle.com/cd/E19120-01/open.solaris/819-2789/about-mirrors-2/index.html",
      "accessed": "2026-10-21"
    },
    {
      "id": "hesela-raid01",
      "title": "Hesela: RAID 0+1 and RAID 1+0 component availability",
      "url": "https://hesela.com/analyses/raid-rebuild-ure-math-and-resilver/#raid01-heading",
      "accessed": "2026-10-21"
    }
  ],
  "provenance": [
    "Source synthesis and an explicitly scoped four-member calculation, not a hardware experiment. The Solaris example is implementation-specific."
  ]
}