Volume Checksums

Volume checksums allow you to verify that the contents of your volume has not been altered outside of Laserfiche. The Laserfiche Server uses an algorithm to create a checksum: a string of information that can be used to compare and detect changes in the volume files. This checksum can then be used to determine whether an image, electronic file, or attachment annotation matches the version the Server is aware of. If the document does not match, the Laserfiche Server will warn the user that the checksum is invalid, and the invalid checksum will be logged. In addition, you can run a volume content verification process in the admin console.

If a user makes a change through Laserfiche, using a client application or an integration, the checksum will be updated and the document's new contents will be considered valid by the Server.  It is only if the volume files are modified outside of Laserfiche (for instance, if someone browses to a volume in Windows Explorer and makes a change to an image), or if data is lost or corrupted in transit, that the checksum will return as invalid.

You can use checksums to ensure that volume file information is valid and consistent, and has not been changed outside of Laserfiche.

Important:  While volume checksums can be used to determine whether a document has been modified outside of Laserfiche, they are not a form of security. You should still secure your volume files in Windows to ensure that unauthorized users do not have access to them.  In addition, an invalid checksum is not necessarily an indication of deliberate tampering: invalid checksums can also appear if there is accidental data loss or corruption (for instance, a failed copy operation, or data loss over a network).

Enabling volume checksums

Enabling checksums for a volume will generate the necessary information to allow the volume's contents to be verified later. When you enable checksums, checksum information will be generated for the files currently in the volume. In addition, whenever files are added to the volume, or modified through Laserfiche, the checksum information for those files will be automatically updated in the background.

The Laserfiche Server will automatically use this checksum to detect when a document is opened whose contents do not match the Server's information about the file. For example, if a bad network connection causes a document to open with data missing, the Laserfiche Windows client can use the checksum to determine that the document is incomplete and warn the user. The document will still open, but with an Invalid Checksum warning. The invalid checksum information will also be logged. You can also use this information to run a content verification on the volume.

Note: Checksums can be enabled on any physical volume, either an independent physical volume or a physical volume within a logical volume. If you enable checksums on the parent logical volume, checksums will automatically be enabled on all future physical volumes created within that logical volume, but will not affect existing physical volumes within that logical volume. To enable checksums for all physical volumes within a logical volume--past and present--you must enable checksums on the parent logical volume, and then on each of the existing physical volumes within that logical volume. New physical volumes created during volume rollover will automatically have checksums enabled.

To enable volume checksums

  1. Start the Laserfiche Administration Console.
  2. In the console tree, expand the desired Laserfiche server item.
  3. Select the desired Laserfiche repository.
  4. If security has been enabled on the selected repository, log in as a user with the Manage Volumes privilege.
  5. Navigate to the Volumes node.
  6. Select the volume on which to enable checksums.
  7. Open the Action menu or right-click, and point to All Tasks. Select Enable Checksums....
  8. Verify that you want to enable checksums on this volume.
  9. The Enable Checksum process will run. This may take several minutes.

Disabling volume checksums

You can disable checksums on a volume that has had checksums enabled. Once volume checksums have been disabled, you will not be able to perform content verification on the volumes unless you re-enable it.

To disable volume checksums

  1. Start the Laserfiche Administration Console.
  2. In the console tree, expand the desired Laserfiche server item.
  3. Select the desired Laserfiche repository.
  4. If security has been enabled on the selected repository, log in as a user with the Manage Volumes privilege.
  5. Navigate to the Volumes node.
  6. Select the volume on which to enable checksums.
  7. Open the Action menu or right-click, and point to All Tasks. Select Disable Checksums....
  8. Verify that you want to disable checksums on this volume.

Validating volume contents

Once you have enabled checksums on a volume, you can perform a volume content validation process to determine whether the contents of the volume match the information generated by the checksum. If a file in the volume does not match the value the Server expects, it will be listed in the Volume Content Verification report, which can also be exported as a .csv file.

Note:  Volume content validation must be performed on the individual volumes within a logical volume, rather than on the parent logical volume.

To perform a volume content validation

  1. Start the Laserfiche Administration Console.
  2. In the console tree, expand the desired Laserfiche server item.
  3. Select the desired Laserfiche repository.
  4. If security has been enabled on the selected repository, log in as a user with the Manage Volumes privilege.
  5. Navigate to the Volumes node.
  6. Select the volume to validate.
  7. Open the Action menu or right-click, and point to All Tasks. Select Validate Checksums.... The validation process will run.
  8. When the validation process is complete, the Volume Content Verification dialog will open. It will list the number of electronic files, image files and attachment files that were checked, as well as the number that contained a mismatch, had no checksum information, or were missing data.
  9. If the validation contains any mismatched or missing data, you can download the checksum validation report to determine exactly what information is erroneous. Click the linked number of mismatched or missing files, or the Download Report button, to download the report.

    10. Note: If all volume contents were valid, no report will be generated.

  10. Click Close to close the dialog.