Checking the Data Integrity of the backup media volumes ensures that the backup data has not been modified after being sent to the backup media.
During various transfers from one media to another, there is a remote possibility that such a change has happened, and restoring from such altered data may not give the desired result.
The Data Integrity page reads and verifies that backed-up data image on the media has not been modified. In the case of application clients (such as Windows Oracle), the check does not proceed beyond determining whether the tape is readable. In this case, the message "Could not determine validation for dumper" is displayed and logged. This message can be safely ignored.
If you verify by date, all the tapes associated with each backup run on the selected date are verified (in most cases, there will be only one run per day). If you verify by the label, only a particular tape is verified. The correct tape(s) must be loaded in the tape device. Verification of each backup run begins by listing the tape(s) required for that run and then prompting you to load each tape as necessary until all have been checked.
The Data Integrity page lets you check out that the already-written media (selected by either date or label) has not been altered after the backup. Run the Data Integrity before restoring a backup image.
Note : Data Integrity Check is not valid if we add Windows related Source with encryption strategy as “AES 256-bit on client”.
Procedure to Check Data Integrity
Select a backupset from drop-down to get options to verify by date or by media label. The default method of invoking a Data Integrity report is by Media label.
From the Verify Data Integrity drop-down box, the method of verification can be changed to By Date. Selecting by date displays the appropriate interface controls.
The By Media Label dialog is displayed in the right panel by default when the backupset is selected. It allows you to select an Amanda tape by volume from the drop-down menu. Click the Verify button to start the data integrity check of the selected tape.
On choosing 'By Date' option, the GUI opens to a page with the Calendar control in the right-hand panel, with the current month selected for display. Use the calendar controls to change as desired.
The Calendar control at the bottom of the panel works the same as it does for the ZMC Report. Click the Verify button to start the data integrity check for all the tapes used by the selected backup date.
The left-hand panel displays the status of the verification process for the selected tape label or date.
It is possible to automate the media verification procedure using amcheckdump command. Please contact the Zmanda Support team if you need more information.