NTSTATUS 0xC05CFF03: meaning and diagnosis

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Description:

another initiator preempted this initiator's persistent reservation.

Could be also:
Constant	Type	OS
ERROR_SVHDX_UNIT_ATTENTION_RESERVATIONS_PREEMPTED	HRESULT	Windows

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STATUS_SVHDX_UNIT_ATTENTION_RESERVATIONS_PREEMPTED

Persistent-reservation ownership was taken away

STATUS_SVHDX_UNIT_ATTENTION_RESERVATIONS_PREEMPTED means a Shared VHDX initiator lost a reservation through a preempt operation. In a guest cluster, that can be an expected part of failover or fencing; it is not a signal for the displaced node to keep issuing writes until its next retry succeeds.

The critical question is whether the preemption matches the cluster manager’s recorded ownership change. A mismatch may indicate a split-brain risk, incorrect reservation keys, or an out-of-band storage operation. The reservation state must be handled by the workload or clustering control plane that owns it.

What to verify

Stop write paths that depend on the lost reservation and identify the current reservation holder.
Compare reservation keys, initiator identities, and cluster failover events around the time of preemption.
Do not use manual raw-SCSI commands to take ownership unless that is an approved recovery procedure for the clustered workload.

References

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