{
  "slug": "iscsi-error-recovery-level",
  "term": "iSCSI Error Recovery Level",
  "aliases": [
    "iSCSI ERL",
    "ErrorRecoveryLevel"
  ],
  "definition": "The iSCSI Error Recovery Level is the session-wide negotiated value from 0 to 2 that selects the protocol recovery capabilities available to an initiator and target.",
  "note": "ErrorRecoveryLevel is negotiated during login, defaults to 0 and resolves to the lower offered value. Level 0 provides session recovery; level 1 adds digest-failure recovery within a command or connection; level 2 adds connection recovery and includes the lower levels. [key] [hierarchy] Implementations must support level 0, while levels 1 and 2 are optional. A supported higher level is not a guarantee that every error is recovered without disruption: implementations may escalate to recovery with a wider scope, and recovery depends on the relevant retained state and protocol rules. [hierarchy] [classes] Discovery sessions use level 0. [discovery] ERL is not a replica count, a durable-write guarantee, or a host multipathing policy; it describes recovery of the iSCSI association and its tasks. The paired analysis explains these boundaries. [analysis]",
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "related": [
    "iscsi",
    "iscsi-session",
    "iscsi-connection",
    "initiator-target"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "key",
      "title": "RFC 7143: ErrorRecoveryLevel; section 13.20",
      "url": "https://www.rfc-editor.org/rfc/rfc7143.html#section-13.20",
      "accessed": "2026-10-17"
    },
    {
      "id": "hierarchy",
      "title": "RFC 7143: Error Recovery Hierarchy; section 7.1.5",
      "url": "https://www.rfc-editor.org/rfc/rfc7143.html#section-7.1.5",
      "accessed": "2026-10-17"
    },
    {
      "id": "classes",
      "title": "RFC 7143: Recovery Classes; section 7.1.4",
      "url": "https://www.rfc-editor.org/rfc/rfc7143.html#section-7.1.4",
      "accessed": "2026-10-17"
    },
    {
      "id": "discovery",
      "title": "RFC 7143: ErrorRecoveryLevel for Discovery Sessions; section 7.4.1",
      "url": "https://www.rfc-editor.org/rfc/rfc7143.html#section-7.4.1",
      "accessed": "2026-10-17"
    },
    {
      "id": "analysis",
      "title": "Hesela: iSCSI identity, sessions and recovery",
      "url": "https://hesela.com/analyses/iscsi-identity-sessions-recovery/",
      "accessed": "2026-10-17"
    }
  ],
  "updated": "2026-10-17"
}