You can restore an entire cluster by using one of the following methods: restore data to a previous point in time or restore data from a backup set (snapshot).
The point in time to which you want to restore data may coincide with the time when a backup set was created. In this case, you can restore data from the backup set (snapshot). If no backup sets were created at the point in time to which you want to restore data, you can only restore data to a previous point in time.
Restoration process
The restoration process is the same regardless of whether you restore data to a previous point in time or from a backup set.
Restore all data to a new cluster.
Verify the accuracy of the data in the new cluster. Then, migrate the restored data back to the original cluster or switch your business to the new cluster.
The following section describes the overall process:
Figure 1. Flowchart for restoring data to a new cluster and then migrating data back to the original cluster
Figure 2. Flowchart for restoring data to a new cluster and switching business to the new cluster
Estimated time required for restoration
The time required for data restoration varies based on the specifications and size of your cluster and the size of the backup set. The following table describes the estimated time required for data restoration.
Procedure | Estimated time | |
Restore data to a new cluster | Create a temporary cluster | 5 to 10 minutes |
Restore data from a backup set (snapshot) | 3 GB/minute | |
Restore data by using redo logs Note Redo logs are used only when you restore data to a previous point in time. | 1.5 GB/minute | |
Compare data in the new cluster | 3 to 5 minutes | |
Migrate the restored data from the new cluster to the original cluster | Cluster size (in KB) × Maximum IOPS × 15% × 16 KB/second | |
For example, if the sizes of a cluster (4 cores, 16 GB memory, maximum IOPS of 32,000), a backup set (snapshot), and redo logs are 100 GB, 10 GB, and 3 GB, you can use the following formulas to calculate the required restoration time:
Time required to restore the data of the backup set (snapshot): 10/3 = 3.3 minutes
Time required to restore data by using redo logs: 3/1.5 = 2 minutes
Time required to migrate the restored data from the new cluster to the original cluster: 100 × 1,024 × 1,024/(32,000 × 15% × 16) = 22.7 minutes
If you restore data to a new cluster and then migrate the restored data from the new cluster to the original cluster, the total required time is 5 + 3.3 + 2 + 3 + 22.7 = 36 minutes.
If you restore data to a new cluster and then switch your business to the new cluster, the total required time is 5 + 3.3 + 2 + 3 + time required to switch business + new cluster configuration time = 13 minutes + time required to switch business + new cluster configuration time.
We recommend that you restore data during off-peak hours.