Help Center> Distributed Cache Service> Service Overview> DCS Instance Types> Single-Node Redis
Updated on 2023-09-28 GMT+08:00
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Single-Node Redis

Each single-node DCS Redis instance has only one node and does not support data persistence. They are suitable for cache services that do not require data reliability.

  • You cannot upgrade the Redis version for an instance. For example, a single-node DCS Redis 4.0 instance cannot be upgraded to a single-node DCS Redis 5.0 instance. If your service requires the features of higher Redis versions, create a DCS Redis instance of a higher version and then migrate data from the old instance to the new one.
  • Single-node instances cannot ensure data persistence and do not support automatic or manual data backup. Exercise caution when using them.

Features

  1. Low system overhead and high QPS

    Single-node instances do not support data synchronization or data persistence, reducing system overhead and supporting higher concurrency. QPS of single-node DCS Redis instances reaches up to 100,000.

  2. Process monitoring and automatic fault recovery

    With an HA monitoring mechanism, if a single-node DCS instance becomes faulty, a new process is started within 30 seconds to resume service provisioning.

  3. Out-of-the-box usability and no data persistence

    Single-node DCS instances can be used out of the box because they do not involve data loading. If your service requires high QPS, you can warm up the data beforehand to avoid strong concurrency impact on the backend database.

  4. Low-cost and suitable for development and testing

    Single-node instances are 40% cheaper than master/standby DCS instances, suitable for setting up development or testing environments.

In summary, single-node DCS instances support highly concurrent read/write operations, but do not support data persistence. Data will be deleted after instances are restarted. They are suitable for scenarios which do not require data persistence, such as database front-end caching, to accelerate access and ease the concurrency load off the backend. If the desired data does not exist in the cache, requests will go to the database. When restarting the service or the DCS instance, you can pre-generate cache data from the disk database to relieve pressure on the backend during startup.

Architecture

Figure 1 shows the architecture of a single-node DCS Redis instance.

For Redis 4.0/5.0/6.0, you can specify a port or use the default port 6379. In the following architecture, port 6379 is used. If you have customized a port, replace 6379 with the actual port.

Figure 1 Single-node DCS Redis instance architecture

Architecture description:

  • VPC

    The VPC where all nodes of the instance run.

    For intra-VPC access, the client and the instance must be in the same VPC.

    DCS Redis 4.0/5.0/6.0 instances do not support public access.

  • Application

    The client of the instance, which is the application running on an Elastic Cloud Server (ECS).

    DCS Redis and Memcached instances are respectively compatible with Redis and Memcached protocols, and can be accessed through open-source clients. For examples of accessing DCS instances with different programming languages, see the instance access instructions.

  • DCS instance

    A single-node DCS instance, which has only one node and one Redis process.

    DCS monitors the availability of the instance in real time. If the Redis process becomes faulty, DCS starts a new process within seconds to resume service provisioning.

Parent topic: DCS Instance Types