How Health Check Works

When Veeam Backup for Google Cloud saves a new restore point to a backup repository, it calculates CRC values for metadata in the backup chain and saves these values to the chain metadata, together with the Cloud SQL instance data. When performing a health check, Veeam Backup for Google Cloud verifies availability of data blocks for each restore point and uses the saved values to ensure that the restore points being verified are consistent.

Veeam Backup for Google Cloud performs the health check in the following way:

1. As soon as the backup policy session completes successfully, Veeam Backup for Google Cloud starts the health check as a new session. For each restore point in the regular backup chain, Veeam Backup for Google Cloud calculates CRC values for backup metadata and compares them to the CRC values that were previously saved to the restore point. Veeam Backup for Google Cloud also checks whether data blocks that are required to rebuild the restore point are available.

If the backup policy session completes with an error, Veeam Backup for Google Cloud tries to run the backup policy again, taking into account the maximum number of retries specified in the automatic retry settings. After the first successful retry (or after the last one out of the maximum number of retries), Veeam Backup for Google Cloud starts the health check.

2. If Veeam Backup for Google Cloud does not detect data inconsistency, the health check session completes successfully. Otherwise, the session completes with an error.

Depending on the detected data inconsistency, Veeam Backup for Google Cloud performs the following operations:

• If the health check detects corrupted metadata in a full or an incremental restore point, Veeam Backup for Google Cloud marks the regular backup chain as corrupted in the configuration database. During the next backup policy session, Veeam Backup for Google Cloud copies the full Cloud SQL instance image, creates a new full restore point and starts a new backup chain in the backup repository.

• If the health check detects corrupted disk blocks in a full or an incremental restore point, Veeam Backup for Google Cloud marks the restore point that includes the corrupted data blocks and all subsequent incremental restore points as incomplete in the configuration database. During the next backup policy session, Veeam Backup for Google Cloud copies not only those data blocks that have changed since the previous backup session but also data blocks that have been corrupted. Veeam Backup for Google Cloud then saves these data blocks to the latest restore point that has been created during the current session.