ApsaraDB for Redis

A key value database service that offers in-memory caching and high-speed access to applications hosted on the cloud

ApsaraDB for Redis is an on-demand database service that is easy to deploy and manage. This service is compatible with Redis protocols.

ApsaraDB for Redis supports highly scalable data storage that can be shared across multiple processes, applications, or servers. This service allows retrieval of data from caches to provide high-speed reading and writing. You can use both memory and disks to ensure data persistence. This service is suitable for high-performance web applications.

Benefits

Cost-effectiveness

Provides more cost-effective caching services at a discount that ranges from 30% to 50%.

Subscription

Supports the subscription billing method. Subscription is suitable for long-term stable workloads. In comparison to pay-as-you-go, subscription saves up to 34% of the total costs.

Excellent Performance

Provides the read/write splitting edition and cluster edition. A read/write splitting instance supports up to five read-only nodes to increase the read performance by five times. Cluster instances are scalable. A cluster instance supports a maximum of 256 shards and up to 4 TB of cache capacity. This allows the cluster instance to process over 10 million queries per second.

Features

  • Simple Key Value Storage

    Facilitates quick deployment of services.


    Provides multiple views of monitoring statistics which can be managed from Alibaba Cloud Management Console for hosted Redis.


    Supports multiple data operations to meet complex user requirements.

  • Compatible

    Compatible with all data types defined in open-source Redis protocol, including string, hash, list, set and sorted set.


    Rapidly deploys Redis-compliant cache services.


    Provides infrastructure provisioning and easy maintenance of cache software.


    Compatible with existing tools or clients like Jedis.

  • Elastic Scaling

    One-click storage capacity expansion:

    Supports elastic scaling of storage capacity without workload interruption. You can scale the storage with only a few mouse clicks in the console.

  • High Availability

    Provides standard master-replica instances, master-replica clusters and read/write splitting instances with master and replica nodes to prevent a single point of failure (SPOF) from disrupting your workloads. You can deploy the service across multiple zones and implement a master-replica replication mechanism.


    Automatically detects hardware failures and provides recovery options to restore services at the earliest opportunity.

  • Reliability

    Provides high-speed data read-write capability.


    Ensures persistent data storage by using memory and hard disk storage mode.


    Offers excellent backup services using master and slave dual nodes.

  • Smooth Transaction Operation

    ApsaraDB for Redis supports transaction function defined in the Redis protocol.


    Implements atomic operation, which consists of multiple commands sent from a single client.

  • Advanced Message Notification Mechanism

    Enables message Pub/Sub function by decoupling the publish client and subscribe client based on event notification mechanism.


    Implements interconnections among multiple clients in hosted Redis.

FAQs

1. Does ApsaraDB for Redis support public network access?

No, ApsaraDB for Redis only supports access within the Alibaba Cloud intranet. Only applications deployed on ECS instances can connect to ApsaraDB for Redis hosting for data operations.

2. What is the default data eviction policy of ApsaraDB for Redis?

The default eviction policy of ApsaraDB for Redis is "no eviction". No keys will be evicted, and no writes will be possible until more memory is freed. You can modify the settings in "Policy Settings" through ApsaraDB for Redis console.

Note: ApsaraDB for Redis adopts volatile-LRU by default, which is different from ApsaraDB for Redis.

3. How can I connect ApsaraDB for Redis to Redis with Command Line Interface?

Using Alibaba Cloud Command Line Interface (CLI), you can run the following command to connect to the ApsaraDB for Redis over Redis:

redis-cli -h instance connection address -a Instance ID:password

Note: ApsaraDB for Redis can only be connected to an ECS Instance in the same node. This is because ApsaraDB for Redis can only be connected with intranet, and not over the Internet with hosts on other nodes.

For more information about Alibaba Cloud CLI, click here click here

4. Do updates on master nodes get automatically synchronized with the associated slave nodes?

Yes, updates on the master node are automatically synchronized with the associated slave node. Alibaba Cloud ApsaraDB for Redis supports asynchronous replication.

5. What is the re-connection mechanism after client time-out?

A client time-out may arise from network problems or due to any other issue with servers. Also, there is no explicit correspondence between request and response in the Redis protocol.

In the case of access time-out to ApsaraDB for Redis, you need to disconnect to avoid protocol errors and set up a connection again.

Note: Although ApsaraDB for Redis is compatible with a majority of Redis clients, some do not have an auto-reconnection mechanism. For such clients, you need to manually reconnect to the ApsaraDB for Redis when a time-out occurs.

6. Which Redis version is ApsaraDB for Redis compatible with?

Alibaba Cloud DB for Redis is compatible with Redis 2.8.19. However, a few commands are still not supported. For more details, see AsparaDB for Redis Document CenterDocument Center.

7. Which Redis features and commands does ApsaraDB for Redis support?

ApsaraDB for Redis supports all Redis features and commands except for a few operations. You can find the list of the unsupported commands herehere.

8. Can I import my Redis data into ApsaraDB for Redis?

Yes, you can easily import all your Redis data into ApsaraDB for Redis. You can read the detailed import instructions herehere.

9. Does ApsaraDB for Redis support Redis LUA scripts?

No, ApsaraDB for Redis does not support Redis LUA scripts.

10. Does ApsaraDB for Redis support "distributed clusters"?

At present, ApsaraDB for Redis instances which are 16GB or above can support distributed cluster instances. These distributed cluster instances provide larger storage capacity and higher processing capability compared to regular instances. You can get more information about ApsaraDB for Redis distributed cluster instances herehere.

11. Does ApsaraDB for Redis cluster instance support hash_tag?

Yes, ApsaraDB for Redis distributed cluster Instances support hash_tag. You can get more information about ApsaraDB for Redis cluster instances through the Document Center Document Center.

12. What is the relationship between ApsaraDB for Redis and Redis?

ApsaraDB for Redis is a key value cloud database service built by Alibaba Cloud and is compatible with the Redis protocol and supports a majority of the Redis commands. You can easily connect with ApsaraDB for Redis for data storage and related operations.

13. Does ApsaraDB for Redis support data persistence?

Yes, ApsaraDB for Redis extends support for data persistence by adopting memory and hard disk data storage mode. However, currently the data persistence mode/frequency is set automatically by ApsaraDB for Redis.

14. Why doesn’t my new ApsaraDB for Redis instance show zero in the beginning?

The product behavior of ApsaraDB for Redis is similar to Redis. However when a new instance is created, a-dictionary class system files of 1-2MB is generated, occupying a fraction of storage space of the instance. Hence, the usage doesn't reflect zero in the beginning on the ApsaraDB for Redis console whenever a new ApsaraDB for Redis instance is created.

15. Does ApsaraDB for Redis support master-slave double node backup?

Yes, synchronization and failover between master and slave nodes are all managed by ApsaraDB for Redis. You don’t need to make any maintenance efforts on your own.

16. Does ApsaraDB for Redis support read-only slave node?

No. ApsaraDB for Redis adopts a master-slave structure in which slave nodes do not support read-only model.

17. Does ApsaraDB for Redis support N slave nodes for one master node?

No, currently the master and slave nodes are mapped one-to-one and work synchronously.

18. Can I customize the hash algorithm for an ApsaraDB for Redis Cluster instance?

No, ApsaraDB for Redis Cluster instance does not support the user-defined hash algorithm. It adopts the standard hash algorithm, followed by Redis Cluster.

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