You can configure the system to automatically allocate read weights for read-only ApsaraDB RDS for SQL Server instances. You can also manually specify read weights for the read-only RDS instances. If you configure the system to automatically allocate read weights, the read weight that is allocated to a read-only RDS instance is fixed. This topic describes the default read weights of read-only RDS instances of different instance types.
You can configure the rules of read weight allocation when you enable the read/write splitting feature. You can also modify the read weights based on your business requirements. For more information, see Enable read/write splitting by enabling the read-only routing endpoint and Modify read weights.
Read-only RDS instances support the general-purpose instance family or the dedicated instance family.
Dedicated instance family
Instance family | Instance type | Number of CPU cores | Memory capacity | Default weight |
Dedicated instance family | mssql.x4.medium.ro | 2 | 8 GB | 800 |
mssql.x4.large.ro | 4 | 16 GB | 1,600 | |
mssql.x4.xlarge.ro | 8 | 32 GB | 3,200 | |
mssql.x4.2xlarge.ro | 16 | 64 GB | 6,400 | |
mssql.x4.4xlarge.ro | 32 | 128 GB | 9,900 | |
mssql.x4.8xlarge.ro | 64 | 256 GB | 9,900 | |
mssql.x8.medium.ro | 2 | 16 GB | 1,600 | |
mssql.x8.large.ro | 4 | 32 GB | 3,200 | |
mssql.x8.xlarge.ro | 8 | 64 GB | 6,400 | |
mssql.x8.2xlarge.ro | 16 | 128 GB | 9,900 | |
mssql.x8.4xlarge.ro | 32 | 256 GB | 9,900 | |
mssql.x10.5xlarge.ro | 40 | 384 GB | 9,900 | |
mssql.x8.8xlarge.ro | 64 | 512 GB | 9,900 |
General-purpose instance family
Instance family | Instance type | Number of CPU cores | Memory capacity | Default weight |
General-purpose instance family | rds.mssql.s3.large | 4 | 8 GB | 800 |
rds.mssql.c1.large | 8 | 16 GB | 1,600 | |
rds.mssql.m1.medium | 4 | 16 GB | 1,600 | |
rds.mssql.c1.xlarge | 8 | 32 GB | 3,200 | |
rds.mssql.c2.xlarge | 16 | 64 GB | 6,400 | |
rds.mssql.c4.xlarge | 32 | 128 GB | 9,900 | |
rds.mssql.c4.2xlarge | 32 | 256 GB | 9,900 |