Data ONTAP 8 uses NTP for time synchronization. It requires a more accurate time source than that provided by Windows DC by default (10 seconds). Therefore, using Windows DCs, Data ONTAP 8 loses time synchronization. If the time difference between the storage system and the DC is greater than 5 minutes, a CIFS authentication failure will occur.
Procedure
To determine the accuracy specified by the Windows DC, use regedit.exe on the Windows DC to examine the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Config\LocalClockDispersion
If the value is the following, it can be concluded that the DC is not configured to report itself as a time source with the accuracy required by NTP:
dword:0000000a.
According to article 2015314: Data ONTAP 8 and later releases fail to synchronize time with Windows w32time NTP server, run the following command on the DC to change the reported accuracy to work with Data ONTAP 8:
w32tm /config /localclockdispersion:0 /update
NetApp KB: https://kb.netapp.com/support/index?page=content&id=1013468
