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April 14, 2010

Netapp NDMP restore issue

Canceled NDMP restores on a NetApp NAS device will zero out the files destined to be restored.


If an NDMP restore on a NetApp NAS device is initiated and then canceled, the files destined to be overwritten by the restore will be zeroed out.  This behavior is normal and is not specific to NetBackup, rather it is a part of the functionality of the NetApp NAS device.

The following is an excerpt from the NetApp Data OnTap manual documenting the flow of a restore:
    1  Data ONTAP catalogs the files that need to be extracted from the tape.
    2  Data ONTAP creates directories and empty files.
    3  Data ONTAP reads a file from tape, writes it to disk, and sets the permissions-including ACLs-on it.
    4  Data ONTAP repeats steps 2 and 3 until all the specified files are copied from the tape.

There are no error messages in any log files, as all products are working as designed.  Note than any canceled NDMP restores can have unexpected results, including data being overwritten with zeros.

If these actions are being performed to determine the tapes necessary for the restore, use the bpimagelist command with the -preview option to list the necessary media

The bpimagelist command with the -d, -e, and -U options allows for the specification of start and end dates (mm/dd/yy format) and having the output formatting in a user friendly mode:

C:\VERITAS\NetBackup\bin\admincmd>bpimagelist -d 09/20/05 -e 09/21/05 -U
Backed Up         Expires       Files       KB  C  Sched Type   Policy
----------------  ---------- -------- --------  -  ------------ ------------
09/21/2005 09:29  10/05/2005        3      224  N  User Backup  server01_windows
09/20/2005 14:59  10/04/2005        3      224  N  Full Backup  server01_windows
09/09/2005 16:26  09/23/2005        5     2016  N  User Backup  server01_sql
09/09/2005 16:26  09/23/2005        5     3296  N  User Backup  server01_sql
09/09/2005 16:25  09/23/2005        5    12064  N  User Backup  server01_sql
09/09/2005 16:25  09/23/2005        5     1376  N  User Backup  server01_sql
09/09/2005 16:24  09/23/2005        5    16480  N  User Backup  server01_sql
09/09/2005 16:24  09/23/2005        0        0  N  Full Backup  server01_sql
09/09/2005 14:29  09/23/2005        4      226  N  Full Backup  server01_windows

Then,  specifying the same command with the -preview option at the end indicates the media IDs used for the backup:

C:\VERITAS\NetBackup\bin\admincmd>bpimagelist -d 09/20/05 -e 09/21/05 -U -preview
CD3643
CD3643
c:\veritas\netbackup\disk_storage_01\server01_1126301216_C1_F1
c:\veritas\netbackup\disk_storage_01\server01_1126301182_C1_F1
c:\veritas\netbackup\disk_storage_01\server01_1126301148_C1_F1
c:\veritas\netbackup\disk_storage_01\server01_1126301114_C1_F1
c:\veritas\netbackup\disk_storage_01\server01_1126301080_C1_F1