Item | ApsaraDB RDS for SQL Server instance | Self-managed database on an ECS instance | Self-managed database on a third-party database server |
Cost-effectiveness | Scalable resources are provided. SQL Server Web Edition is supported to increase cost-effectiveness. A free quota on backup storage is provided. The free quota is equal to half the purchased storage capacity. For more information, see Backup storage fees of an ApsaraDB RDS for SQL Server instance. Internet traffic is free of charge.
| Scalable resources are provided. SQL Server Web Edition is not supported. You are charged for the backup storage that you use. You are charged for the Internet traffic that you consume.
| The initial investment cost is high. SQL Server Web Edition is not supported. You must allocate independent backup resources. This requires high costs. You are charged for the Internet traffic that you consume and the domain names that you use. The domain names are charged at high prices.
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Availability | In RDS Basic Edition, your database system requires approximately 15 minutes to complete a failover. In RDS High-availability Edition or RDS Cluster Edition, your database system runs in a proprietary high-availability architecture of Alibaba Cloud. This architecture allows your database system to complete a failover within 30 seconds. In RDS Cluster Edition, you can create read-only RDS instances to balance loads in your database system. For more information, see Overview of read-only ApsaraDB RDS for SQL Server instances. In RDS Cluster Edition, you can use read/write splitting to distribute read and write requests by using a read/write splitting endpoint. For more information, see Overview of read/write splitting.
| In the basic edition, your databases require approximately 30 minutes to complete a failover. You must purchase additional software or hardware to build a high-availability architecture. You must configure or purchase additional software or hardware to build a load balancing architecture.
| Your databases are standalone. If a database server breaks down, repairs can take hours to weeks. You must purchase additional software or hardware to build a high-availability architecture. You must configure or purchase additional software or hardware to build a load balancing architecture.
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Reliability | Automated replication of data between primary and secondary RDS instances, data backups, and log backups are supported to ensure high data reliability. RDS Cluster Edition delivers an RPO of 0.
| Your databases are highly available only when they are deployed in an optimal high-availability architecture. To ensure an RPO of 0, you must purchase independent R&D services. This requires high costs.
| Data reliability is moderate and varies based on the corruption probability of individual disks. To ensure an RPO of 0, you must purchase independent R&D services. This requires high costs.
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Usability | An automated backup and restoration system is provided to support point in time recovery (PITR) and database-level backup and restoration. In addition, streaming backups are supported to minimize the impacts on performance. For more information, see Enable automatic backups for an ApsaraDB RDS for MySQL instance. An automated monitoring and alerting system allows you to monitor all supported metrics at the instance and database levels and view monitoring information that is collected over a time range of a few seconds. If the value of a metric exceeds the specified threshold, ApsaraDB RDS sends you an alert by text message, email, or DingTalk. In addition, a free quota for alert notifications over text messages is provided based on your purchase details. For more information, see Configure an alert rule for an ApsaraDB RDS for SQL Server instance. Geo-disaster recovery is in development.
| Automated backups are not supported. You must purchase or configure the streaming backup and PITR features. This requires high costs. You must purchase an independent monitoring system and configure the system in the CloudMonitor console. Technical challenges are imposed on usability.
| Automated backups are not supported. You must purchase or configure the streaming backup and PITR features. This requires high costs. You must purchase or configure an independent monitoring system. This requires high costs. Remote data centers require high costs and are difficult to be built. As a result, geo-disaster recovery is difficult to be implemented.
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Performance | RDS instances that run SQL Server 2008 R2 with local SSDs provide high performance. RDS instances that run SQL Server 201x support next-generation compute-storage decoupling and can benefit from hardware dividends. RDS instances that are equipped with ESSDs provide higher performance than RDS instances that are equipped with local SSDs or standard SSDs. You can create read-only RDS instances to improve performance and balance loads. You can use the advanced optimization capabilities that are provided by DAS. For more information, see Overview of DAS.
| If you choose local disks, data reliability is reduced. If you choose cloud disks, you must plan a disk architecture. This requires high costs. The parameters of the RDS instances that use ESSDs are optimized and adapted. In this case, RDS instances that use ESSDs have higher performance than self-managed SQL Server databases on ECS instances. The cluster edition is difficult to be deployed and requires high consultancy costs and high maintenance costs. You must recruit experienced DBAs. This requires high costs.
| Database servers are updated at lower speeds than cloud computing hardware. Therefore, self-managed databases on these servers are inferior to RDS instances. Computing-storage separation is difficult to be implemented and may require you to spend millions of US dollars on advanced storage media. The cluster edition is difficult to be deployed and requires high consultancy costs and high maintenance costs. You must recruit experienced DBAs. This requires high costs.
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Security | | IP address whitelists, security groups, and VPCs can be used to control access to ECS-hosted self-managed databases. Link encryption and disk encryption must be separately configured to protect data. This requires high consultancy costs. SQL logs are difficult to be audited because they must be separately stored.
| IP address whitelists and VPCs can be used to control access to self-managed databases on third-party servers. This requires high consultancy costs. Link encryption and disk encryption must be separately configured to protect data. This requires high consultancy costs. SQL logs are difficult to be audited because they must be separately stored.
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Legal liability | ApsaraDB RDS for SQL Server is provided with a valid license. No legal liabilities are imposed on you. | You must purchase a valid license. | You must purchase a valid license. Otherwise, legal liabilities may be imposed on you. |