GaussDB(DWS) Snapshot Overview

A snapshot is a full or incremental backup of a GaussDB(DWS) cluster at a specific point in time. It records the current database data and cluster information, including the number of nodes, node specifications, and database administrator name. You can back up and restore clusters using snapshots. Snapshots can be created manually or automatically. For details, see Creating and Managing a GaussDB(DWS) Snapshot and Configuring and Managing GaussDB(DWS) Automated Snapshots. For details about how to restore a snapshot, see Restoring a GaussDB(DWS) Cluster.

The snapshot backup and restoration rates are listed below. The rates are obtained from the test environment with local SSDs as the backup media. The rates are for reference only. The actual rate depends on your disk, network, and bandwidth resources.

Backup rate: 200 MB/s/DN
Restoration rate: 125 MB/s/DN

Notes and Constraints

Backing up the cluster is essential for maintaining data reliability, especially when the service provider cannot restore data through upstream re-import. This helps prevent data loss caused by human or other factors.
The cluster versions that support schema-level snapshots are listed below. If the current console interface does not support this feature, contact technical support.
- 9.1.0.100 or later
- 8.3.0.110 or later 8.3.0.xxx
- 8.2.1.230 or later 8.2.1.2xx
OBS snapshot storage space and billing description
- The cluster storage is provided by GaussDB(DWS) free of charge. Cluster storage = Storage space per node x Number of nodes
- GaussDB(DWS) provides some free-of-charge storage space for you to store snapshot data generated in cluster backup. However, if you use more space than the free-of-charge storage space, the exceeded part is charged as per OBS billing rules. For details, see the OBS pricing details.
The dependency of the snapshot service is as follows:
- The snapshot management function depends on OBS or NFS.
- If the backup device is an NFS backup media, the NFS backup media must be mounted to the high-performance SFS Turbo. For details, see 11.1.3.2 Automatic Snapshot Policy.
- Only the snapshots stored in OBS can be used to restore data to a new cluster.
The new GaussDB(DWS) cluster created based on the snapshot must have the same configurations as the original cluster. That is, the number and specifications of nodes, memory, and disks in the new cluster must be the same as those in the original cluster.
If you create a cluster based on a snapshot without modifying parameters, the parameters of the new cluster will be the same as those of the snapshot.
Only storage-compute decoupled clusters of 9.0.2 and later versions support snapshots. However, those with elastic logical clusters do not support backup and restoration. If an elastic logical cluster exists in the cluster, the backup and restoration will fail. You are advised to reclaim the elastic logical cluster before performing the backup and restoration.
To perform snapshot restoration of a GaussDB(DWS) storage-compute decoupled cluster billed in hybrid mode, you can choose either yearly/monthly or pay-per-use billing. For example, if the cluster has three nodes of each billing type, restoring the cluster will change the billing mode of all six nodes to either pay-per-use or yearly/monthly.
During snapshot creation, do not perform the VACUUM FULL operation, or the cluster may become read-only.
Snapshot creation affects disk I/O performance. You are advised to create snapshots during off-peak hours.
During the snapshot creation, some intermediate files are retained, which occupy extra disk space. Therefore, create snapshots in off-peak hours and ensure that the disk capacity usage is less than 70%.