A global database network (GDN) consists of multiple PolarDB clusters that are deployed in multiple regions. Data is replicated across all clusters in each GDN. This allows applications that are deployed across different regions to access a database that is local to their region, which provides reliable access with low latency. This topic describes how to create and release a GDN.
Prerequisites
A PolarDB cluster is created as the primary cluster in a GDN.
Supported regions and clusters
Regions: GDN is available in more than 10 regions, including regions inside the Chinese mainland, the China (Hong Kong) region, and regions outside China. For more information, see Region mappings between the primary and secondary clusters.
Clusters:
Database Edition is Enterprise Edition, and Edition is Cluster Edition.
Database Engine:
MySQL 8.0.2.
MySQL 8.0.1 with revision version 8.0.1.1.17 or later.
MySQL 5.7 with revision version 5.7.1.0.21 or later.
MySQL 5.6 with revision version 5.6.1.0.32 or later.
The following limits also apply:
A GDN consists of one primary cluster and up to four secondary clusters.
NoteTo add more secondary clusters, go to Quota Hub, find the quota item based on the quota ID
polardb_mysql_gdn_region
, and click Apply in the Actions column.The primary cluster and secondary clusters must use the same database engine version. Supported versions are MySQL 8.0, MySQL 5.7, and MySQL 5.6.
A cluster belongs to only one GDN.
Clusters in a GDN can be serverless clusters or serverless-enabled clusters with defined specifications. When the database engine of the primary cluster meets the following conditions, all clusters in the GDN must have at least one read-only node.
PolarDB for MySQL 8.0.1 with revision version 8.0.1.1.42 or later.
PolarDB for MySQL 8.0.2 with revision version 8.0.2.2.23 or later.
For non-serverless secondary clusters in a GDN, each compute node must have at least 4 CPU cores.
Clusters in a GDN do not support the database and table restoration feature.
Clusters in a GDN support the in-memory column index (IMCI) feature. However, before you add read-only IMCI nodes to a cluster, you must contact us to enable GDN support for IMCI by adding the feature to whitelists.
Usage notes
If you want to create a secondary cluster in a region outside Chinese mainland for a GDN, you must sign the PolarDB Cross-border Data Transfer Compliance Commitment.
The following table lists the region mappings between the primary and secondary clusters in a GDN.
Region of the primary cluster
Region of the secondary cluster
All regions in Chinese mainland
In the same region as the primary cluster or in a region in Chinese mainland other than the region where the primary cluster is deployed.
For example, if the primary cluster is in the China (Hangzhou) region, secondary clusters can be in the China (Hangzhou) region or other regions in Chinese mainland.
NoteIf you want to deploy the secondary cluster in other regions, contact us.
Regions outside Chinese mainland
China (Hong Kong), Japan (Tokyo), South Korea (Seoul), Singapore, Malaysia (Kuala Lumpur), Indonesia (Jakarta), Philippines (Manila), Thailand (Bangkok), Germany (Frankfurt), US (Silicon Valley), US (Virginia), UK (London).
Pricing
You are not charged for the traffic that is generated during cross-region data transmission within a GDN. You are charged only for the use of PolarDB clusters in the GDN. For more information, see Billing.
Create a GDN
Log on to the PolarDB console. In the left-side navigation pane, click Global Database Network.
On the Global Database Network page, click Create GDN.
In the Create GDN dialog box, configure the following parameters.
Parameter
Description
Name
The name of the GDN that you want to create. We recommend that you specify a descriptive name that makes it easy to identify. GDN names do not have to be unique.
Primary Region
The region where the primary cluster is deployed.
NoteSelect the region where the primary cluster is deployed.
Primary Cluster
Select an existing cluster as the primary cluster of the GDN.
After you create a GDN, you can add secondary clusters. For more information, see Manage a secondary cluster.
Release a GDN
Find the GDN that you want to release and click Delete in the Actions column.
ImportantA GDN can be released if it contains only the primary cluster.
A GDN cannot be restored after it is released. Proceed with caution.
Applications that are connected to the endpoints of a GDN cannot access databases after the GDN is released. Modify the application code to change the connection string of the GDN at the earliest opportunity.
Log on to the PolarDB console. In the left-side navigation pane, click Global Database Network.
FAQ
References
Related API operations
Operation | Description |
Creates a GDN | |
Deletes a GDN. | |
Queries the information about a GDN. |