Service Tiers
Azure SQL Database service tiers are different for each purchasing model. The DTU-based purchasing model offers Basic, Standard, and Premium tiers. Table 2.4 lists some of the common characteristics of these tiers.
TABLE 2.4 DTU-based purchasing model service tier characteristics
| Characteristic | Basic | Standard | Premium |
| DTUs | 5 | S0: 10 S1: 20 S2: 50 S3: 100 S4: 200 S6: 400 S7: 800 S9: 1600 S12: 3000 | P1: 125 P2: 250 P4: 500 P6: 1000 P11: 1750 P15: 4000 |
| Included Storage | 2 GB | 250 GB | P1–P6: 500 GB P11 and above: 4 TB |
| Maximum Storage | 2 GB | S0–S2: 250 GB S3 and above: 1 TB | P1–P6: 1 TB P11 and above: 4 TB |
| Maximum backup retention | 7 days | 35 days | 35 days |
| CPU | Low | Low, Medium, High | Medium, High |
| IOPS | 1–4 IOPS per DTU | 1–4 IOPS per DTU | >25 IOPS per DTU |
| IO Latency | 5 ms (read), 10 ms (write) | 5 ms (read), 10 ms (write) | 2 ms (read/write) |
| Columnstore Indexes | N/A | S3 and above | Supported |
| In-Memory OLTP | N/A | N/A | Supported |
The vCore-based purchasing model offers the following three service tiers:
- General Purpose is used for most business workloads. This tier offers balanced compute and storage options.
- Business Critical is used for business applications that require high I/O performance. It is also the best option for applications that require high resiliency to outages by leveraging a SQL Server Always On availability group for HA.
- Hyperscale is used for very large OLTP databases (>4 TB) and can automatically scale storage and compute. Hyperscale databases use local SSDs for local buffer-pool cache and data storage. Long-term data storage is done with remote storage.
Table 2.5 lists the common characteristics for the vCore-based purchasing model service tiers:
TABLE 2.5 vCore-based purchasing model service tier characteristics
| Characteristic | General Purpose | Business Critical | Hyperscale |
| Storage | Uses remote storage. Provisioned Compute: 5 GB–4 TB Serverless Compute: 5 GB–4 TB | Uses local SSD storage Provisioned Compute: 5 GB–4 TB | Supports up to 100 TB |
| Availability | 1 replica, no read-scale replicas | 3 replicas, 1 read-scale replica | 1 read-write replica, 0–4 read-scale replicas |
| In-Memory | Not Supported | Supported | Partial Support |