You must understand and resolve any known technical issues before you upgrade your storage system to Data ONTAP 8.2 and later releases.
This topic summarizes significant issues known at publication time. Be sure to check the "Important Cautions" section in the latest Release Notes for your target Data ONTAP release to see a complete list of issues that could affect the upgrade.
As a result, you must install Data ONTAP management software versions that are supported by Data ONTAP 8.2 or later.
Windows Server 2008 and Windows Server 2012 interpret the LUNs with new revision numbers as new disks and set them offline after a host reboot; this status is shown in Windows management interfaces after the upgrade. Windows Server 2003 ignores LUN revision numbers.
Your systems can experience this problem if you are upgrading from a Data ONTAP 8.1 release prior to 8.1.2P4, if deduplication is enabled on any FlexVol volume, and if a FlexVol volume or the associated aggregate is more than 70 percent full.
Licenses installed prior to Data ONTAP 8.2 continue to work after you upgrade to Data ONTAP 8.2 or later. However, if you need to reinstall a license when you are running Data ONTAP 8.2 or later, the old key is not accepted.
By default, the SP automatic update functionality is enabled. You have the option to manually trigger an SP update.
Therefore, after upgrading to this version of Data ONTAP, you might experience an increase in the number of disk failures for certain disk shelf and disk models.
To avoid this issue, you should remain in Data ONTAP 8.1.x.
You cannot upgrade to Data ONTAP 8.2 or later 8.2.x releases if you have Flash Cache modules enabled in your 3210 or 3140 system.
During the intermediate upgrade, if you modify the state of deduplication on a volume, then a storage system disruption may occur.
If vFiler units are present, they might not be initialized for the duration of the CIFS startup time. The delay in CIFS startup is typically due to network infrastructure issues related to domain controllers and LDAP servers.