Help Center> Distributed Cache Service> Service Overview> What Is DCS?
Updated on 2023-09-28 GMT+08:00
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What Is DCS?

Huawei Cloud Distributed Cache Service (DCS) is an online, distributed, fast in-memory cache service compatible with Redis. It is reliable, scalable, usable out of the box, and easy to manage, meeting your requirements for high read/write performance and fast data access.

  • Usability out of the box

    DCS provides single-node, master/standby, read/write splitting, Proxy Cluster, and Redis Cluster instances with specifications ranging from 128 MB to 2048 GB. DCS instances can be created with just a few clicks on the console, without requiring you to prepare servers.

    DCS Redis 4.0, 5.0, and 6.0 instances are containerized and can be created within seconds.

  • Security and reliability

    Instance data storage and access are securely protected through HUAWEI CLOUD security management services, including Identity and Access Management (IAM), Virtual Private Cloud (VPC), Cloud Eye, and Cloud Trace Service (CTS).

    Master/Standby and cluster instances can be deployed within an availability zone (AZ) or across AZs.

  • Auto scaling

    DCS instances can be scaled up or down online, helping you control costs based on service requirements.

  • Easy management

    A web-based console is provided for you to perform various operations, such as restarting instances, modifying configuration parameters, and backing up and restoring data. RESTful application programming interfaces (APIs) are also provided for automatic instance management.

  • Online migration

    You can create a data migration task on the console to import backup files or migrate data online.

DCS for Redis

DCS for Redis supports Redis 4.0/5.0/6.0.

Redis is a storage system that supports multiple types of data structures, including key-value pairs. It can be used in such scenarios as data caching, event publishing/subscribing, and high-speed queuing, as described in Application Scenarios. Redis is written in ANSI C, supporting direct read/write of strings, hashes, lists, sets, sorted sets, and streams. Redis works with an in-memory dataset which can be persisted on disk.

DCS Redis instances can be customized based on your requirements.

  • DCS for Redis 4.0/5.0
    Table 1 DCS for Redis 4.0/5.0

    Instance type

    DCS for Redis provides the following types of instances to suit different service scenarios:

    • Single-node: Suitable for caching temporary data in low reliability scenarios. Single-node instances support highly concurrent read/write operations, but do not support data persistence. Data will be deleted after instances are restarted.
    • Master/standby: Each master/standby instance runs on two nodes (one master and one standby). The standby node replicates data synchronously from the master node. If the master node fails, the standby node automatically becomes the master node. You can split read and write operations by writing to the master node and reading from the standby node. This improves the overall cache read/write performance.
    • Proxy Cluster: In addition to the native Redis cluster, a Proxy Cluster instance has proxies and load balancers. Load balancers implement load balancing. Different requests are distributed to different proxies to achieve high-concurrency. Each shard in the cluster has a master node and a standby node. If the master node is faulty, the standby node on the same shard is promoted to the master role to take over services.
    • Redis Cluster: Each Redis Cluster instance consists of multiple shards and each shard includes a master node and multiple replicas (or no replica at all). Shards are not visible to you. If the master node fails, a replica on the same shard takes over services. You can split read and write operations by writing to the master node and reading from the replicas. This improves the overall cache read/write performance.
    • Read/write splitting: A read/write splitting instance has proxies and load balancers in addition to the master/standby architecture. Load balancers implement load balancing, and different requests are distributed to different proxies. Proxies distinguish between read and write requests, and sends them to master nodes or standby nodes, respectively.

    Instance specifications

    DCS for Redis provides instances of different specifications, ranging from 128 MB to 1024 GB.

    Open-source compatibility

    DCS instances are compatible with open-source Redis 4.0/5.0/6.0.

    Underlying architecture

    Containerized deployment on physical machines. 100,000 QPS at a single node for a Redis 4.0/5.0 instance, 150,000 QPS for a single-node Redis 6.0 basic edition instance, and 170,000 QPS for a master/standby Redis 6.0 basic edition instance.

    High availability (HA) and disaster recovery (DR)

    All instances except single-node ones can be deployed across AZs within a region with physically isolated power supplies and networks.

    For more information about open-source Redis, visit https://redis.io/.