This document describes the basic method to create an instance on the SCS management console.
Create Redis Instance
Log in to the cloud database SCS management console and select the region where the instance is located at the upper left corner.For details on the regions, see [Instructions for Region Selection](https://cloud.baidu.com/doc/SCS/s/fjwvxtowm#Switch Availability Zone#)
Click「Create Instance」，to enter the instance purchase page.Choose billing mode:
Pre-paid：The fees are paid on a yearly and monthly basis and by prepaid mode. The billing price for the pre-paid mode based on the instance specifications and duration is lower than the on-demand billing
Post-paid：The fees are paid on an on-demand manner basis and in post-paid mode; the real-time fee calculation and deduction are based on the instance specifications and duration and its billing method is more flexible than the yearly and monthly billing method
Region information
Option
Description
Current region
You cannot change the region after purchase. If it is changed to another region, switch it on the main navigation page
The instance only supports the access to the devices in the same VPC. Make sure that the instance is created in the same region as the BCC instances to be linked
Availability zone
Multi-AZ are supported in some regions:
Single-AZ: The access delay can be decreased, but the advantage of disaster recovery across data centers is lost
Multi-AZ: The database availability can be increased, but the access delay is also increased
Configuration Information
Option
Description
Engine type
Redis
Architecture type
Different instance architecture types are suitable for different scenarios, and the change is not supported after creatione
Standard Version：The Redis instance with the standard architecture contains only one multipart. It is compatible with Redis 3.2/4.0 protocol and command and is the most common instance type.
Cluster version：A Redis instance with a cluster architecture contains multiparts and multiple proxy nodes. It is compatible with Redis 3.2 protocol and command, adopts a distributed architecture, and supports horizontal and vertical capacity scaling (which is about to put it into use). The cluster instances can expand the data capacity and improve network/CPU/QPS capabilities quickly by horizontally expanding the number of multiparts, and can carry much higher traffic capacity than the standard instances.
Engine version
4.0: Support the standard version
3.2: Support the standard and cluster versions
Storage type
High-performance memory: Use the memory to store full data sets, and have excellent performance
Node specifications
They are the specifications of the cache nodes used to save the data. The cache nodes with different specifications can provide different capacities and performances. For more information, see Redis Standard Version and Redis Cluster Version
Number of multiparts
It is applicable for cluster instances only. A multipart is a set of cache nodes. When an instance contains several multiparts, the data set is hashed to several multiparts, and there is a subset of the complete data set in each multipart. The total capacity of the instance is equal to the product of the capacity of a single cache node multiplied by the number of multiparts
Number of replicas
Depending on the number of selected replicas, each multipart contains a different number of cache nodes：
Single replica: a single multipart contains only one node, which acts as a readable/writable master node. A single-replica instance supports high read/write concurrency, but does not support backup or persistence and does not provide data reliability; it is suitable for business scenarios with low cache data reliability
Double replica: A single multipart contains 2 nodes, of which one node acts as a read/write master node, and the other one acts as standby node that cannot be read or written and is not visible to the user. When the master node fails, the standby node is automatically upgraded to the master node. The double-replica instance supports second-level failover, backup and persistence, with high reliability and high availability, and is suitable for various application scenarios
Instance Information
Option
Description
VPC
It means the visual private cloud (VPC).The cloud database SCS instance allows access to the devices within the same VPC and the BCC instances to be created must be linked to the same VPC.Only selection of "general-purpose" subnets is supported.Any change is not supported after creation.
Port
The optional port is 1025-65534, 22222 is not supported, and the default port is 6379.Any change is not supported after creation
Instance name
It consists of uppercase and lowercase letters, numbers, and special symbols such as "-_ /.". It must start with a letter, with length of 1-64 bits. The name cannot be repeated.
Instance password
Not set temporarily: You can set or modify the password at any time after the instance is created
Set immediately: Set the password below
Automatic backup
It is not applicable to single-replica instances.When it is enabled, the system automatically performs an RDB snapshot backup of the dataset at the specified time.You can modify the default backup policy by setting the backup policy
Purchase Information
Option
Description
Duration
It is only applicable to the prepaid billing mode.There is an extra discount for the duration of 1 year and above
Number of instances
Purchase the instances with same specifications in batches
Auto renewal
It is only applicable to the prepaid billing mode.It is required to avoid any service suspension due to failure to perform renewal in time when the service is expired.
