NDMP Incremental Backups are producing the following warning in the backup logs:
NDMP: WARNING 3: DUMP: Cannot find the data that describes base dump.
NDMP: WARNING 4: DUMP: Cannot open meta file required by incremental dump.
Also, the context of the dump messages may show something like this:
NDMP: NORMAL 1: DUMP: creating "/vol/cifs_XXYZZZ_users01/../snapshot_for_backup.915" snapshot.
NDMP: NORMAL 2: DUMP: Using inowalk incremental dump for Full Volume
NDMP: WARNING 3: DUMP: Cannot find the data that describes base dump.
NDMP: WARNING 4: DUMP: Cannot open meta file required by incremental dump.
NDMP: NORMAL 5: DUMP: Date of this level 1 dump: Tue Apr 12 00:35:13 2016.
NDMP: NORMAL 6: DUMP: Date of last level 0 dump: Mon Sep 7 18:00:03 2015.
*Note the timestamp of when NDMP detected the last Level 0 compared to the current Level 1
As you can see, it may suggest that the last full backup as shown here was 8 months prior, but this is likely not the case.
If you are routinely doing a Weekly or Monthly Level 0 with a differential subset of Level 1s or Incremental sequence of 1,2,3...., then it would be unlikely that NDMP would detect this much time has elapsed between the last Level 0.
So why is this gap being reported when in fact there has not been such a time gap?
Reason 1:
This was found to be caused by the NDMP Backup Options.
Reason 2:
It was discovered that the NDMP Level 0 Backup included the option to "Backup Sub-Volumes individually"
The incremental did not have this selection. These check boxes were left blank.
Analysis:
It appears that when the same option is not selected in the "NDMP Backup Options" (aside from the DUMP LEVEL) for the previous Level, that it will find the last backup that had the same options and use that.
So, since the Level 1 did not have option checked, it referenced back to last Full that also did not.
These selections are part of the metadata that NDMP was looking for. Since it was unable to find the metadata it required, but still had a FULL to reference, it just matched the Level 1 to the FULL it did reference, thus the backup still ran successfully, but backed up a much larger data set than what would be expected due to the differential data change of 8 months.
For more information on this topic, please see the Module 4-Advanced Administration Part Two-Web-based Training
To make sure the Level 0 and subsequent level dumps are in sync, use the same + additional selections for the Level 1 backups and up.
If you are using the option for "Backup sub-volumes individually" for the Level 0, then the Level 1 should use BOTH of the following options:
-Backup sub-volumes individually
-Backup sub-volumes ONLY
Please Note: (For Backup sub-volumes ONLY)
Use this option in conjunction with the option Backup sub-volumes Individually to back up the qtree data while excluding all the non-qtree
files and directories from the backup. This option is useful since the Plug-in for NDMP does not allow you to uncheck child level items. Instead of selecting individual qtrees, you can select the parent volume, and then select this option to exclude the non-qtree data.
IMPORTANT: The backup will fail if there are no qtrees in the selected volume.
