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Reservation conflicts on shared storage are reported when ESXi host displays purple diagnostic screen (2030787)

Symptoms

  • ESXi host experiences a vmkernel error.
  • Reservation conflicts on shared storage are reported when ESXi host displays purple diagnostic screen
  • SCSI I/O operations may fail on other hosts that have access to shared storage. A SCSI sense code indicates a reservation conflict. The sense code event in the vmkernel log looks similar to:

    ScsiDeviceIO: 1672: Command 0x28 to device "naa.60060e801603dd00000103dd00000123" failed H:0x0 D:0x18 P:0x3 Possible sense data: 0x0 0x0 0x0.

  • Virtual machine may not be able to successfully start on other hosts.  This may impact a cluster configured for High Availability.
  • VMFS volumes may be inaccessible from other hosts that have access to shared storage.

Cause

This issue may occur in two scenarios:
  • Concurrent purple diagnostic screen and complete path failure to device

    ESXi hosts that experience a complete path failure to a storage device while generating a purple diagnostic screen cannot release reservations to that device. ESXi requires valid paths to the storage device to release the reservations at the time of the purple diagnostic screen. This may occur regardless of which multipathing plug-in (MPP) is being used.

  •  Purple diagnostic screen while using third party MPP that converts SCSI-2 reservations to SCSI-3 reservations.

    One of the responsibilities of the pluggable storage architecture (PSA) and multipathing plugin (MPP) is to handle SCSI reservation related operations. If ESXi VMkernel experiences a failure and displays a purple diagnostic screen, ESXi attempts to release SCSI-2 and SCSI-3 reservations that have been obtained by the PSA stack. These reservations do not include any reservations obtained exclusively by multipathing extension modules such as MPP. These reservations can be created if the MPP converts SCSI-2 reservations to SCSI-3 reservations. Since third party MPP are capable of performing reservations that are not known to the PSA stack, the reservations may not be released upon VMkernel failure.

Resolution

The ESXi host that generated the purple diagnostic screen needs to be rebooted to release the reservation.

Additional Information

If you experience these symptoms and are currently using a third party MPP, you may be required to engage the third party for assistance and/or remove the third party MPP as a troubleshooting step. For more information, see Third Party Hardware and Software Support Policy.

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