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What Is DCS?

Updated at: Mar 17, 2020 GMT+08:00

HUAWEI CLOUD Distributed Cache Service (DCS) is an online, distributed, in-memory cache service compatible with Redis and Memcached. 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, and cluster instances with specifications ranging from 128 MB to 1 TB. DCS instances can be created with just a few clicks on the console, without requiring you to prepare servers.

    DCS Redis 4.0 and 5.0 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.

For details on how to select a cache engine, see Selecting a Cache Engine.

DCS for Redis

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 publication/subscription, and high-speed queuing, as described in Application Scenarios. Redis is written in ANSI C, supporting direct read/write of strings, hashes, lists, sets, streams, and sorted sets. Redis works with an in-memory dataset which can be persisted on disk.

DCS Redis instances can be customized based on your requirements.

Table 1 DCS Redis instance configuration

Instance type

DCS for Redis provides the following three 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 writes operations by writing to the master node and reading from the standby node. This improves the overall cache read/write performance.

Cluster: Each cluster DCS instance consists of multiple shards and each shard includes a master node and zero or multiple replicas. Shards are not visible to users. If the master node fails, a standby node in the same shard takes over. The use of shards increases cache capacity and concurrent connections. You can split read and writes operations by writing to the master node and reading from the standby node. This improves the overall cache read/write performance.

Instance specification

DCS for Redis provides instances of different specifications, ranging from 128 MB to 1 TB.

Redis version

DCS instances are compatible with open-source Redis 3.0, 4.0, and 5.0.

Underlying architecture

Standard Redis based on VMs: supports up to 100,000 queries per second (QPS) at a single node.

High availability (HA) and DR

Master/Standby and cluster DCS Redis instances can be deployed across AZs in the same region with physically isolated power supplies and networks.

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

DCS for Memcached

Memcached is an in-memory key-value caching system that supports read/write of simple strings. It is often used to cache backend database data to alleviate load on these databases and accelerate web applications. For details about its application scenarios, see Memcached Application Scenarios.

In addition to full compatibility with Memcached, DCS for Memcached provides the hot standby and data persistence.

Table 2 DCS Memcached instance configuration

Instance type

DCS for Memcached provides the following two 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, but does not support read/write operations. If the master node fails, the standby node automatically becomes the master node.

Memory

Specification of single-node or master/standby DCS Memcached instances: 2 GB, 4 GB, 8 GB, 16 GB, 32 GB, and 64 GB.

HA and DR

Master/Standby DCS Memcached instances can be deployed across AZs in the same region with physically isolated power supplies and networks.

For more information about open-source Memcached, visit https://memcached.org/.

DCS Video Introduction

Watch the following video to learn more about DCS.

Distributed Cache Service

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