Constraints

CPU and memory

GeminiDB Redis API supports proxy cluster, Redis Cluster, and primary/standby instances.

• For details about specifications of different instance types, see Instance Specifications.
• You can change the specifications to meet your service requirements by following Changing the CPU and Memory Specifications of an Instance.

Storage space

The storage space depends on the selected instance specifications.

Storage capacity can be scaled up or down. For details, see Scaling Disk Space.

Connections

The maximum value is the number of instance nodes multiplied by 10,000.

The maximum number of connections varies depending on the memory. For details, see Instance Specifications.

Tag

A maximum of 20 tags can be added for each instance.

For more information, see Tag Management.

Free backup space

GeminiDB Redis API provides free backup storage for backup data.

For more information, see Backup Storage.

Retention period

The default value is 7 days. The value ranges from 1 to 3660 days.

For more information, see Configuring an Automated Backup Policy.

Instance name

• Contains 4 to 64 characters.
• Must start with a letter. Only letters (case-sensitive), digits, hyphens (-), and underscores (_) are allowed.

Backup name

• Contains 4 to 64 characters.
• Must start with a letter. Only letters (case sensitive), digits, hyphens (-), and underscores (_) are allowed.

Parameter template name

• Contains 1 to 64 characters.
• Only letters (case sensitive), digits, hyphens (-), underscores (_), and periods (.) are allowed.

Password of database administrator rwuser

• Contains 8 to 32 characters.
• Contains at least two types of the following characters: uppercase letters, lowercase letters, digits, and special characters ~!@#%^*-_=+? For more information, see Changing the Administrator Password of a GeminiDB Redis Database.
• Keep your password secure. The system cannot retrieve it if it is lost.

Database port

Port number for accessing an instance

You can specify a port number, which ranges from 1024 to 65535 except 2180, 2887, 3887, 6377, 6378, 6380, 8018, 8079, 8091, 8479, 8484, 8999, 12017, 12333, and 50069.

If you do not specify a port number, port 6379 is used by default.

VPC

After a GeminiDB Redis instance is created, the VPC where the instance is deployed cannot be changed.

Security group

A security group controls access between GeminiDB Redis API and other services. Ensure that the security group you selected allows your client to access the instance.

If no security group is available, the system creates one for you.

Access control

A load balancer address does not support security groups. After an instance is created, configure IP address access control. If no whitelist is configured, all IP addresses that can communicate with the VPC can access the instance.

ACL account

GeminiDB Redis API provides enterprise-grade multi-tenancy. You can add read-only or read/write accounts for your instance to control access to each database to avoid misoperations from other tenants. A maximum of 200 ACL accounts can be created for each instance.

For more information, see ACL Account Management.

Database access

• If remote access is not enabled, GeminiDB Redis instances and their associated ECSs must be in the same VPC subnet.

• The security group must allow access from the associated ECS.

  By default, a GeminiDB Redis instance cannot be accessed through an ECS in a different security group. You need to add an inbound rule to the security group.

• The default port number of a GeminiDB Redis instance is 6379.
• The database port can be set when an instance is created and can be changed after the instance is created.

Instance deployment

The servers where instances are deployed are not directly visible to you. You can only access the instances through IP addresses and database ports.

Restarting a GeminiDB Redis instance

• GeminiDB Redis instances cannot be rebooted through commands. They must be rebooted on the console.
• Restarting an instance will interrupt services, so off-peak hours are the best time. Ensure that your application can be reconnected.

Viewing GeminiDB Redis instance backups

GeminiDB Redis instance backups are stored in OBS buckets and are invisible to you.

Changing the CPU or memory of a GeminiDB Redis instance

• Second-level intermittent disconnection occurs once when the specifications are changed on a single node. Therefore, the entire instance is intermittently disconnected several times. Ensure that the client can be reconnected. You are advised to change the specifications during off-peak hours.
• For a node whose specifications are being changed, its computing tasks are handed over to other nodes. Change specifications of nodes during off-peak hours to prevent instance overload.

Primary/Standby switchover

Only primary/standby GeminiDB Redis instances are supported. During a primary/standby switchover, the instances are disconnected for less than 10 seconds, which can cause slow latency or command execution failures. Ensure commands can be retried or the client can be reconnected. You are advised to perform the switchover during off-peak hours.

Data restoration

To prevent data loss, you are advised to back up key data before data restoration.

Storage space

If the storage space of an instance is full, data cannot be written to databases. You are advised to periodically check the storage space.

GeminiDB Redis instance storage can be automatically scaled up in case of a sudden surge in data volumes. Enable autoscaling by following Automatically Scaling Up Disk Space.

Recycle bin

• You can move unsubscribed yearly/monthly instances and deleted pay-per-use instances to the recycle bin. You can restore an instance that was deleted up to 7 days ago from the recycle bin.
• The recycling policy is enabled by default and cannot be disabled. Instances in the recycle bin are retained for 7 days by default, and this will not incur any charges.
• Currently, you can put up to a maximum of 100 instances into the recycle bin.
• If you delete an instance in the storage-full status, it will not be moved to the recycle bin.