Amazon Aurora
User Guide for Aurora (API Version 2014-10-31)

Understanding Aurora Backup Storage Usage

Aurora stores continuous backups (within the backup retention period) and snapshots in Aurora backup storage. To control your backup storage usage, you can reduce the backup retention interval, remove old manual snapshots when they are no longer needed, or both. For general information about Aurora backups, see Backups. For pricing information about Aurora backup storage, see the Amazon Aurora Pricing webpage.

To control your costs, you can monitor the amount of storage consumed by continuous backups and manual snapshots that persist beyond the retention period. Then you can reduce the backup retention interval and remove manual snapshots when they are no longer needed.

You can use the Amazon CloudWatch metrics TotalBackupStorageBilled, SnapshotStorageUsed, and BackupRetentionPeriodStorageUsed to review and monitor the amount of storage used by your Aurora backups, as follows:

  • BackupRetentionPeriodStorageUsed represents the amount of backup storage used, in gibibytes, for storing continuous backups at the current time. This value depends on the size of the cluster volume and the amount of changes you make during the retention period. However, for billing purposes it doesn't exceed the cumulative cluster volume size during the retention period. For example, if your cluster size is 100 GiB and your retention period is two days, the maximum value for BackRetentionPeriodStorageUsed is 200 (100 GiB + 100 GiB).

  • SnapshotStorageUsed represents the amount of backup storage used, in gibibytes, for storing manual snapshots beyond the backup retention period. Manual snapshots taken within the retention period don't count against your backup storage. All automatic snapshots also don't count against your backup storage. The size of each snapshot is the size of the cluster volume at the time you take the snapshot. The SnapshotStorageUsed value depends on the number of snapshots you keep and the size of each snapshot. For example, suppose you have one snapshot outside the retention period and cluster volume size was 100 GiB when that snapshot was taken. The amount of SnapshotStorageUsed is 100.

  • TotalBackupStorageBilled represents the sum, in gibibytes, of BackupRetentionPeriodStorageUsed and SnapshotStorageUsed, minus an amount of free backup storage which equals the size of the cluster volume for one day. For example if your database size is 100 GiB, you have one 1 retention day, and you have one snapshot outside the retention period, the TotalBackupStorageBilled is 100 (100 GiB + 100 GiB - 100 GiB).

  • These metrics are computed independently for each Aurora DB cluster.

You can monitor your Aurora clusters and build reports using CloudWatch metrics through the CloudWatch console. For more information about how to use CloudWatch metrics, see Overview of Monitoring Amazon RDS and the table of metrics in Amazon RDS Metrics.

The backtrack setting for an Aurora DB cluster doesn't affect the volume of backup data for that cluster. Amazon bills the storage for backtrack data separately. You can also find the backtrack pricing information on the Amazon Aurora Pricing webpage.

If you share a snapshot with another user, you are still the owner of that snapshot. The storage costs apply to the snapshot owner. If you delete a shared snapshot that you own, nobody can access it. To keep access to a shared snapshot owned by someone else, you can copy that snapshot. Doing so makes you the owner of the new snapshot. Any storage costs for the copied snapshot apply to your account.