nvme-host-identifier · shipping · also NVMe Host ID, HOSTID

NVMe Host Identifier

The NVMe Host Identifier identifies which controllers in an NVM subsystem belong to the same host for purposes including reservation rights.

Related Observatory article: NVMe Host Identifier on hesela.com

Matching nonzero Host Identifiers group controllers under one host's reservation rights; the reservation key is separate. [1] Base 2.3 treats zero identifiers on two controllers as different hosts. Zero-associated reservations and registrations do not survive Controller Level Reset, and changing zero to nonzero does not transfer those associations. Host Identifier is non-saveable; PCIe defaults to zero and NVMe over Fabrics requires 128 bits. [3] Do not extrapolate these lifecycle rules to all earlier or later NVMe versions.

Relations

related
nvme-reservation, multipath-nvme, namespace-nvme

Citations

  1. NVM Express Base Specification 2.0c (2022), sections 5.27.1.25, 7.2-7.5 and 8.19. Copyright 2008-2022 NVM Express, Inc. All rights reserved. (accessed 2026-10-16)
  2. Storage fencing: why a lost heartbeat does not stop writes (accessed 2026-10-16)
  3. NVM Express Base Specification 2.3 (2025), section 5.2.26.1.32, pp. 438-440: Host Identifier and transport-specific lifecycle rules. (accessed 2026-10-16)

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