2016-02-24 04:26 PM
The host settings are applied correctly on all of our hosts. We are still on ESXi 5.5, so that could be it. The APD was in micro/seconds so it was "almost" transparent. It occurred during the cutover phase of the vol move.
2016-02-25 09:27 AM
NetApp Bug report 844098 desribes this issue:
When using ESX/ESXi NFS clients with NetApp storage controllers, you might experience the following issues: Issue 1: Intermittent NFS APDs on VMware ESXi 5.5 U1 When running ESXi 5.5 Update 1, the ESXi host intermittently loses connectivity to NFS storage and an All Paths Down (APD) condition to NFS volumes is observed. This issue is resolved in ESXi 5.5 Express Patch 04. Refer to the VMware KB articles http://kb.vmware.com/kb/2076392 or http://kb.vmware.com/kb/2077414 for instructions to install the patch. Issue 2: Random disconnection of NFS exports under workloads with an excessive number of requests On some NetApp storage controllers with NFS enabled, you might experience the following symptoms: - The NFS datastores appear to be unavailable (greyed out) in vCenter Server, or when accessed through the vSphere Client. - The NFS shares disappear and reappear again after few minutes. - Virtual machines located on the NFS datastore are in a hung/paused state when the NFS datastore is unavailable. This issue is most often seen after a host upgrade to ESXi 5.x or the addition of an ESXi 5.x host to the environment.
Chasing down the bug report trail indicates that the 2nd issue is corrected in all up-to-date cDots.
If you will remain on ESX 5.5 and with NFS - you definitely want the indicated patch. For me a typical data store is about 2-3TB used, higher end hits 8TB, all NFS, and I move them at will as needed without any concern for system load. VMWare never notices anything out of the ordinary.
Hope this helps.
Lead Storage Engineer | Consilio LLC
NCIE SAN Clustered, Data Protection
Kudos and accepted solutions are always appreciated.