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After repeated SAN path failovers, operations that involve VMFS changes might fail for all hosts accessing a particular LUN (1009899)

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  • On rare occasions, after repeated path failovers to a particular SAN LUN, attempts to perform such operations as VMFS datastore creation and vMotion may fail on all ESX/ESXi hosts accessing this LUN.
  • In the log files, you see the warning:

    I/O failed due to too many reservation conflicts.
    Reservation error: SCSI reservation conflict

  • In ESXi 4.1, you see an error similar to:

    WARNING: FS3: 7096: Reservation error: Timeout


If you see the reservation conflict messages on all hosts accessing the LUN, this indicates that the problem is caused by the SCSI reservations for the LUN that are not completely cleaned up and no host can use the LUN.


This is a known issue affecting VMware 4.x and 5.1.x.

Currently, there is no resolution

To work around this issue, remove the SCSI reservation by running the LUN reset command from any system in the cluster:

vmkfstools -L lunreset /vmfs/devices/disks/device ID

Additional Information

Update History

10/17/2011 - Updated Products to include ESX/ESXi 4.1 12/03/2012 - Updated symptoms for ESXi 4.1

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