Before you create a Tair (Redis OSS-compatible) instance, you need to select the most cost-effective and stable instance type that suits your performance, price, scenario, and workload needs. For example, you may want to use instances as high-speed caches or in-memory databases. This topic describes the instance types, disaster recovery solutions, architectures, and instance specifications of Tair (Redis OSS-compatible) to help you select the appropriate instances.
Selection references
Select an instance type
Tair (Redis OSS-compatible) provides Redis Open-Source Edition and Tair (Enterprise Edition). Tair (Enterprise Edition) is an enterprise-level, in-memory database service that is developed based on the business practices of Alibaba. Tair (Enterprise Edition) introduces multiple series types of instances based on storage mediums such as dynamic random-access memory (DRAM), NVM, and SSDs or Enterprise SSDs (ESSDs) to meet your requirements for low-latency access, data persistence, and reduced overall costs. Tair (Enterprise Edition) provides you with higher performance, more data structures, and more flexible storage methods to help you meet business requirements in different scenarios.
For information about the commands and parameters supported by each series type, see Command overview and Configure instance parameters.
The following table describes the instance types.
Comparison item | Redis Open-Source Edition | Tair (Enterprise Edition) | ||
Cloud-native (recommended) Classic | Cloud-native | |||
Storage medium | Memory | |||
Compatible Redis versions | 5.0, 6.0, and 7.0 | 5.0, 6.0, and 7.0 | 6.0 | 6.0 |
Performance | 100% (benchmark) | 300% | 90% | Up to 60% |
Cost | 100% (benchmark) | Approximately 117% (calculated at a monthly discount of 30% off) | Approximately 70% | 15% to 20% |
Features | Open source Redis services on the cloud. |
|
| Combines disks and memory to provide an optimal balance between data persistence and quick access to data. |
Scenarios | Use scenarios of open source Redis. |
| Scenarios that require high performance and reduced costs for processing a large amount of data, such as Internet of Things (IoT). | Scenarios that require large storage space and high access performance to store warm and cold data and take cost as the primary consideration, such as indexing of file storage and long-term storage of historical messages. |
For more information about the differences in features and performance between Redis Open-Source Edition and Tair (Enterprise Edition), see Comparison between Tair (Enterprise Edition) and Redis Open-Source Edition.
Select a disaster recovery solution
Tair (Redis OSS-compatible) provides three disaster recovery solutions: single-zone high-availability (HA) solution, zone-disaster recovery solution, and cross-region disaster recovery solution. You can select a disaster recovery solution based on your business requirements.
Disaster recovery solution | Description | Operation |
The master and replica nodes are deployed on different machines in the same zone to provide machine-level fault recovery capabilities. | On the buy page, set Deployment Type to Single-zone Deployment. | |
The master and replica nodes are deployed in different zones (data centers) of the same region to provide data center-level fault recovery capabilities. | On the buy page, set Deployment Type to Dual-zone Deployment. | |
Multiple child instances are deployed in different regions to form a Global Distributed Cache instance. This solution provides region-level (natural disaster) fault recovery capabilities. For more information, see Global Distributed Cache. | For more information, see Create a distributed instance. |
Select an architecture
Tair (Redis OSS-compatible) supports the standard architecture (with cluster mode disabled), the cluster architecture, and the read/write splitting feature (optional). You can select an architecture that suits your business data volume and your requirements for read and write capabilities and business performance.
Instance architecture | Architecture model | Data distribution | Scenario | Read/write splitting |
One shard, using a master-replica model. | All data is stored in a single shard. |
| You can enable or disable the read/write splitting feature. If you enable read/write splitting, you can specify the number of read replicas. Each instance can consist of one master node and up to nine read replicas. | |
Consists of a proxy node and multiple shards. Each shard uses a master-replica model. | Data is distributed across shards. |
| You can enable or disable the read/write splitting feature. Each shard can consist of one master node and up to four read replicas. |
Select instance specifications
You must select the appropriate instance specifications and quantities (shard specifications and number of shards) based on a comprehensive estimation of business metrics such as capacity, bandwidth, number of connections, and QPS. We recommend that you keep your usage below 80% of the total resources you acquire.
When you estimate the capacity, you do not need to consider the memory overhead caused by the write-time replication of forks and advanced features such as whitelist configuration, audit logging, large key management, and hotkey management. The preceding memory overhead is borne by Alibaba Cloud and is not included in the memory size of the purchased instance.
Large keys are a common issue in Redis usage. If the total capacity of a cluster is large and the capacity of a single shard is small, when large keys are generated, the capacity of the shard where the large keys reside is more likely to be exhausted.
The following table describes the recommended shard specifications for the cluster architecture.
Total instance capacity | Recommended shard specifications |
16 GB to 64 GB | 2 GB or higher |
64 GB to 256 GB | 4 GB or higher |
Greater than 256 GB | 8 GB or higher |
If the selected instance type does not meet your business requirements, you can change the instance configurations at any time. For more information, see Change the configurations of an instance.