Parameter Name | Parameter Description |
Billing Mode | Only supports pay-as-you-go billing mode. |
Region | The region of the read-only instance is fixed and matches that of the source instance. It cannot be changed. |
Availability Zone | Select whether to enable multiple availability zone deployment. Settings can be adjusted based on actual highly available business requirements. |
Database Version | The database version is fixed and matches that of the source instance. It cannot be changed. |
Architecture Type | The architecture type is fixed and matches that of the source instance. It cannot be changed. For specific information about the architecture type, see System Architecture. |
Storage Engine | The default storage engine is WiredTiger. |
Mongod Specification | Select the compute specifications for the database instance from the dropdown list. The CPU core number and memory capacity of a read-only instance must be equal to or greater than those of the source instance, with higher specifications resulting in higher IOPS. For specific supported specifications, see Product Specification. After creating an instance, you can adjust its compute specifications. For specific operations, see Adjusting Instance Configuration. |
MongoDB Shard Quantity | When the architecture type is set to Sharded Cluster, this parameter is displayed. It is used for setting the number of shards in the sharded cluster, with a value range of [1,20]. The shard quantity of a read-only instance must be greater than or equal to that of the source instance. Each shard is a replica set. Increasing the shards quantity can enhance the cluster's storage capacity. Select as needed. After creating an instance, you can adjust the MongoDB shard quantity. For specific operations, see Adjusting Instance Configuration. |
Disk Capacity | Select the database instance's storage capacity on the slider. The disk capacity of a read-only instance must be greater than or equal to that of the source instance. MongoDB specifications differ, hence the range of disk capacities varies. See Product Specification. The system by default allocates 10% of the selected storage capacity for Oplog's storage space. The size of Oplog can be adjusted in the console instance list. For specific operations, see Adjusting Oplog Storage Capacity. After creating an instance, you can adjust the instance's disk capacity. For specific operations, see Adjusting Instance Configuration. |
Primary/Secondary Nodes Quantity | When the architecture type is set to replica set, this parameter is displayed. The default is 3 nodes (1 primary, 2 secondaries), with three storage nodes forming a one-primary-two-secondary architecture. Custom replication numbers are not currently adjustable. You may select from the dropdown list: 5 nodes (1 primary, 4 secondaries), or 7 nodes (1 primary, 6 secondaries). After creating a read-only instance, you can increase the number of secondary nodes. For specific operations, see Adding Secondary Node. |
Primary/Secondary Nodes Quantity per Shard | When the architecture type is set to Sharded Cluster, this parameter is displayed. It is used for setting the number of nodes in each shard of the sharded cluster, with the default being 3 nodes (1 primary, 2 secondary nodes), meaning each shard follows a one-primary-two-secondary, three-node architecture. You can select from the dropdown list: 5 nodes (1 primary, 4 secondary nodes), or 7 nodes (1 primary, 6 secondary nodes). Custom node numbers are not currently supported. After creating the instance, you can increase the number of secondary nodes per shard. For specific operations, see Adding Secondary Node. |
Read-Only Node Quantity | Setting the number of read-only nodes, supporting 0 to 5 read-only nodes. Only versions 4.0 and 4.2 support configuring the number of read-only nodes; version 3.6 does not support this. After creating a read-only instance, you can increase the number of read-only nodes. For specific operations, see Adding Read-Only Node. |
Configuration Instructions | Based on the configured MongoDB specification, calculate the maximum number of connections per instance to help you predict whether the current specification meets expectations. |
Mongos Specifications | When the architecture type is set to Sharded Cluster, this parameter is displayed. It is used for configuring Mongos specifications. After configuring the MongoDB specification, Mongos will have default specification configurations. For example, if MongoDB is set to 2-core 4GB, Mongos is automatically configured for 1-core 2GB by default. Upgrading the Mongos specification will incur charges. For pricing, see Product Pricing. The connection limit for a sharded cluster will be determined by the Mongos specifications and quantities you choose. You can view the maximum number of connections in the Configuration Instructions. After creating an instance, you can change the Mongos configuration. For specific operations, see Changing Mongos Node Configuration Specifications. |
Mongos Quantity | When the architecture type is set to Sharded Cluster, this parameter is displayed. It is used for configuring the number of Mongos. If the instance deployment is in the same availability zone, the range of Mongos numbers is [3, 32]. If the multi-availability zone deployment is enabled and the instance deployment is across different availability zones, then the range of Mongos numbers is [6, 32]. Increasing the number of Mongos will incur charges. For pricing, see Product Pricing. After creating an instance, you can adjust the number of Mongos. For specific operations, see Add New Mongos Node. |
Network Type | Only Virtual Private Cloud is supported. |
IPv4 Network | Select a specific Virtual Private Cloud and its subnet. It is recommended to select the same Virtual Private Cloud in the same region as the cloud server. A Virtual Private Cloud has a region attribute (e.g., Guangzhou), while a subnet has an availability zone attribute (e.g., Guangzhou Zone 1). A Virtual Private Cloud can be divided into one or more subnets. Subnets under the same Virtual Private Cloud are by default inter-connected through intranet, whereas Virtual Private Clouds (whether in the same region or not) are by default isolated from each other. After purchasing an instance, you can switch the Virtual Private Cloud. For specific operations, see Switch Instance Network. You can also click Create a New Virtual Private Cloud and Create a New Subnet to recreate the required network environment. For specific operations, see Creating Virtual Private Cloud. |
IPv6 Network | Enable/disable IPv6 access. Currently not supported. |
Security Group | Set security group rules for the instance to control inbound traffic to the database. You can select an existing security group from the dropdown menu, or click Custom Security Group to set new inbound rules for the security group. For detailed information, see Configuring Security Group. |
Specify Project | Allocate the instance to the corresponding project. You can manage instances by project. |
Tag | Set tags for your instance. You can classify and manage instances based on tags. Click Add to select tag keys and values. |
Instance Name | Set the instance name, with a default of 500. Set a recognizable name. Supports Chinese, English, and numbers with a length less than 60, including hyphens "-" and underscores "_". |
Purchase Quantity | A single instance can support up to 3 read-only instances. |
Total Fees |
Parameter | Parameter Description |
Instance ID | Read-only instance ID and its name. Click the instance ID in blue font to jump to the read-only instance details page. For more information, see Viewing Instance Details. |
Status | The current running status of the instance. When it is normal, it should be Running. |
Specification | Instance specification information. It includes memory and disk capacity. |
Latency | The read-only instance is based on the synchronization status from the source instance, and its latency. |
Nodes Quantity | The number of primary and secondary nodes in a read-only instance. |
Network | The name of the Virtual Private Cloud to which the read-only instance belongs. |
Private Network Address | The private IPv4 address assigned by the Virtual Private Cloud. When accessing the database, the private IP address and its port information need to be configured. For specific operations, see Connecting to MongoDB Instance. |
Region | Information about the region and availability zone. |
Operation | By clicking configuration changes, you can adjust the specifications of the read-only instance. When adjusting the specifications of the source instance, be sure to synchronously upgrade the specifications of the read-only instance; otherwise, data loss may occur. |
APIs | Description |
Queries the list of MongoDB instances. | |
Modifies the instance name. |
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