esx.problem.storage.apd.timeout
Summary
Device or filesystem has entered the All Paths Down Timeout state after being in the All Paths Down state for N seconds. I/Os will be fast failed.
Causes
All paths down timeout has expired for the storage device.
Resolutions
For more information on the problem and resolution steps, see this VMware KB article.
External
Refer to the VMware Online Documentation for more information on vCenter event messages and possible solutions.