Back up and Validate

If you select your backup plan in the main window and then pick “Back up and Validate…” from the menu, Arq backs up your files but for each object that has already been uploaded (by a prior backup) Arq verifies the existing object’s contents.

This feature is only enabled for storage locations that do not have APIs that return checksums, including folder/NAS and SFTP.

WARNING: Validation will download a significant amount of data from your storage location. If your storage location has data-transfer-out fees this will incur a cost. Also, the increased data transfer may affect you if your ISP has a data cap.

Arq downloads the contents of each existing blob, calculate its checksum, and verify it’s the correct checksum.

If an existing object is missing or doesn’t contain the expected contents, Arq uploads the correct contents to replace it.

Note: If you just want to make sure all the objects that Arq expects still exist at the storage location:

1. Stop any backup activity.
2. Click on your backup plan and pick “Clear Cache” from the menu.
3. Start a backup.

Arq will query the storage location for the list of existing objects and will populate its database with all existing backup records, logging errors for any backup record that is incomplete. Then it will create a new backup record, uploading any objects that need to be uploaded.