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How NVFAIL protects database files

When booting up or while taking over in a failover configuration, Data ONTAP checks for NVRAM errors. If no errors are detected, start the file service is started normally. However, if NVRAM errors are detected Data ONTAP stops database instances from responding.

When you enable the nvfail option, one of the following processes takes place during bootup.
If... Then...
Data ONTAP detects no NVRAM errors File service starts normally.
Data ONTAP detects NVRAM errors and you use the optional nvfail_rename file
  1. Data ONTAP returns a stale file handle (ESTALE) error to NFS clients trying to access the database. This causes the application to stop responding, crash, or shut down. Data ONTAP then sends an error message to the system console and log file.
  2. Data ONTAP renames database files specified in the nvfail_rename file by appending .nvfail to the original file names, making those files unavailable to both CIFS and NFS clients.
Data ONTAP detects NVRAM errors and you do not use the optional nvfail_rename file
  1. Data ONTAP returns a stale file handle (ESTALE) error to NFS clients trying to access the database, causing the application to stop responding, crash, or shut down. Data ONTAP then sends an error message to the system console and log file.
  2. No database files are renamed. When the application restarts, files are available to CIFS clients, even if you have not verified that they are valid. For NFS clients, files remain inaccessible as long as the file system is not remounted.
Data ONTAP detects NVRAM errors on a volume that contains LUNs and you use the optional nvfail_rename file
Note: The term LUNs in this context refers to the LUNs that Data ONTAP serves to clients, not to the array LUNs used for storage on a storage array.
  1. Data ONTAP takes the LUNs offline in the volume that had the NVRAM errors.
  2. Data ONTAP stops exporting those LUNs over iSCSI or FCP.
  3. Data ONTAP sends error messages to the system console and log file stating that Data ONTAP took the LUNs offline or that NFS file handles are stale (useful if the LUN is accessed over NAS protocols).
  4. Data ONTAP renames LUNs specified in the nvfail_rename file by appending .nvfail to the original LUN names.
Data ONTAP detects NVRAM errors on a volume that contains LUNs and you do not use the optional nvfail_rename file
  1. Data ONTAP takes the LUNs offline in the volume that had the NVRAM errors.
  2. Data ONTAP stops exporting those LUNs over iSCSI or FCP.
  3. Data ONTAP sends error messages to the system console and log file stating that Data ONTAP took the LUNs offline or that NFS file handles are stale (useful if the LUN is accessed over NAS protocols).
  4. No database files are renamed. When the application restarts, files are available to CIFS clients, even if you have not verified that they are valid. For NFS clients, files remain inaccessible as long as the file system is not remounted.