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Storage PDL responses may not trigger path failover in vSphere 6.0 (2144657)

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Symptoms

ESXi 6.0 may not failover to an alternate available path after encountering a Permanent Device Loss (PDL) condition on the active path.

Note: For additional symptoms and log entries, see the Additional Information section.

Purpose

Upgrading to ESXi 6.0 Update 2 resolves this issue.

Cause

An inadvertent change in PDL multipathing behavior in ESXi 6.0 results in alternative working paths for a LUN not being checked if a PDL condition/error is detected. When encountering a PDL condition on the active path, the ESXi host initiates a health check against the remaining paths but does not fail over if another path is responsive/healthy.

The correct response is to failover to one of the healthy working paths. As a result is, the host is no longer able to issue I/O to these LUNs until the ESXi host is rebooted. 

Resolution

This issue is resolved in ESXi 6.0 Update 2 and later, available at VMware Downloads.

To work around this issue if you do not want to upgrade, restart the ESXi host.

Additional Information

You experience these additional symptoms:
  • In the /var/log/vmkernel.log file on the ESXi host, you see path-evaluation activity followed by I/O failures associated with SCSI sense code  H:0x8:

    cpu6:32909)WARNING: NMP: nmp_PathDetermineFailure:2961: Cmd (0x2a) PDL error (0x5/0x25/0x0) - path vmhba2:C0:T5:L2 device naa.514f0c5ec2000008 - triggering path evaluation
    cpu6:32909)WARNING: NMP: nmp_PathDetermineFailure:2961: Cmd (0x2a) PDL error (0x5/0x25/0x0) - path vmhba2:C0:T5:L2 device naa.514f0c5ec2000008 - triggering path evaluation
    cpu6:32909)WARNING: NMP: nmp_PathDetermineFailure:2961: Cmd (0x28) PDL error (0x5/0x25/0x0) - path vmhba2:C0:T5:L2 device naa.514f0c5ec2000008 - triggering path evaluation
    cpu6:32909)WARNING: NMP: nmp_PathDetermineFailure:2961: Cmd (0x28) PDL error (0x5/0x25/0x0) - path vmhba2:C0:T5:L2 device naa.514f0c5ec2000008 - triggering path evaluation
    [ ... ]
    cpu28:36724)NMP: nmp_ThrottleLogForDevice:3286: Cmd 0x2a (0x43a61055c5c0, 36134) to dev "naa.514f0c5ec2000008" on path "vmhba1:C0:T6:L2" Failed: H:0x8 D:0x0 P:0x0 Possible sense data: 0x0 0x0 0x0. Act:EVAL
    cpu14:36168)NMP: nmp_ThrottleLogForDevice:3286: Cmd 0x89 (0x439e11581700, 32806) to dev "naa.514f0c5ec2000008" on path "vmhba2:C0:T7:L2" Failed: H:0x8 D:0x0 P:0x0 Possible sense data: 0x0 0x0 0x0. Act:EVAL


    Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

  • Lack of failover to the alternate path result in aborted I/O, this can cause LUN availability issues which in turn cause virtual machine failures.
  • The PDL condition may be encountered on a subset (but not all) paths during non-disruptive upgrade events on certain storage platforms.
  • The LUN and datastore do not return to availability after this event until the original path is available again or the ESXi host is rebooted. 

See Also

Request a Product Feature

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