Heads up! LUNs attached to VMware vSphere 6.0 hosts may remain in APD Timeout state

28 July VMware released a knowledgeable article describing a problem with ESXi 6.0 and the All Path Down (APD).

The problem is that a LUN that have experienced an APD state never exist the APD state and the LUN is not accessible from the ESXi host even though the connection between the ESXi host and the datastore has been established.

Currently there is not fix or workaround that will guarantee to get the LUN back online but there are recommended actions when this happens:

  • Follow VMware KB 2014155 to kill outstanding I/O to a LUN and maybe also restart the ESXi host management agents.
  • Reboot the ESXi host.

Good news is that not all APD event will see this behaviour but i have not been able to find the exact once yet. Will update the blog post when/if i do.

For additional information, please read VMware KB 2126021