Azure SQL Database

 Azure SQL Database

Pricing

Type

1.Single Database 

2.Elastic Pool

Purchase Model

1.DTU ( 5 ~ 4000)

pay one fixed price for your compute (or IO/memory), as well as your data storage and back up retention

DTU簡化選擇時需要考量的因素(CPU、Memory、Disk)，也就是選擇的等級越高可用資源越高

2.vCore

separate charges for your compute (what type of node or compute power you’re using) and a separate charge for your storage. Using vCore you have more flexibility in managing your costs than with DTU.

選擇考量

1.Purchase Model可以在資源建立之後做修改，隨時可以切換

2.DTU模式提供相較於vCPU費用較低的選項，故評估期間可以考慮先用DTU

If you have software assurance with Microsoft and are familiar with how that works, there are some advantages there to using vCore. If you’re not familiar with software assurance, you may want to start with the DTU model.

SERVICE TIER:

General Purpose

Business Critical

Hyperscale

Compute Tier: (DTU沒有此選項)

Provisioned

Serverless 

• 非使用中期間自動暫停資料庫
• 在有活動傳回時自動繼續執行資料庫
• 根據工作負載需求自動擴縮計算，並以每秒使用的計算量來計費

效能設定

• minimum vCores 和 maximum vCores 均為可設定的參數，其定義資料庫可用計算容量的範圍。 記憶體和 IO 限制會與指定的虛擬核心範圍成比例。 
• 自動暫停延遲是可設定的參數，其定義資料庫在自動暫停前必須處於非使用中的時間期間。 資料庫會在下一個登入或其他活動發生時自動繼續。 或者，您也可以停用自動暫停。

成本

• 無伺服器資料庫的成本總計為計算成本和儲存體成本的加總。
• 當計算使用量介於所設定的下限和上限之間時，計算成本會以所使用的虛擬核心和記憶體為基礎。
• 當計算使用量低於所設定的下限時，計算成本會以所設定的最小虛擬核心和最小記憶體為基礎。
• 當資料庫暫停時，計算成本為零，而且只會產生儲存體成本。
• 儲存體成本的決定方式與已佈建的計算層相同。

	SERVICE TIER	COMPUTE TIER	HEARDWARE TYPE		Storage、Backup Storage、Long Term Retention
vCPU	General Purpose	Provisioned	Standard-series (Gen 5) Fsv2-series DC-series	INSTANCE : 2 vote ~ 80 vCore Compute- REDUNDANCY: Local/Multi-Availability Zone Instances
vCPU	General Purpose	Serverless	Standard-series (Gen 5)	Billed vCores: REDUNDANCY: Local/Multi-Availability Zone Maximum vCores、 Minimum vCores、 CPU Used (vCores)、Memory used (GB)、Duration
vCPU	Business Critical	n/a	Standard-series (Gen 5) Fsv2-series DC-series	INSTANCE : 2 vCore ~ 80 vCore
vCPU	Hyperscale	n/a	Standard-series (Gen 5) DC-series	INSTANCE : 2 vCore ~ 80 vCore Compute ? instance x 730 hours High Availability Replicas ? x 1 x 730

	SERVICE TIER	PERFORMANCE LEVEL	Database	Storage	Long Term Retention
DTU	Basic	B: 5 DTUs, 2GB included storage per DB	? Database x 730 hour	n/a	Average database size during retention period 5 GB
DTU	Standard		? Database x 730 hour	n/a	Average database size during retention period 5 GB
DTU	Premium		? Database x 730 hour	500GB 750GB 1TB	Average database size during retention period 5 GB

DTU 

The following table compares the Basic, Standard, and Premium service tiers.

	Basic	Standard	Premium
Uptime SLA	99.99%	99.99%	99.99%
Maximum storage size	2 GB	1 TB	4 TB
Maximum DTUs	5	3000	4000
IOPS (approximate)*	1-4 IOPS per DTU	1-4 IOPS per DTU	>25 IOPS per DTU
Maximum backup retention	7 days	35 days	35 days
Columnstore index	Not supported	Supported for S3 and above	Supported
In-memory OLTP	Not supported	Not supported	Supported

https://learn.microsoft.com/en-us/azure/azure-sql/database/service-tiers-sql-database-vcore?view=azuresql

Use case	General Purpose	Business Critical	Hyperscale
Best for	Most business workloads. Offers budget-oriented, balanced, and scalable compute and storage options.	Offers business applications the highest resilience to failures by using several high availability secondary replicas, and provides the highest I/O performance.	The widest variety of workloads, including those with highly scalable storage and read-scale requirements. Offers higher resilience to failures by allowing configuration of more than one high availability secondary replica.
Compute size	2 to 128 vCores	2 to 128 vCores	2 to 128 vCores1
Storage type	Premium remote storage (per instance)	Super-fast local SSD storage (per instance)	De-coupled storage with local SSD cache (per compute replica)
Storage size1	1 GB – 4 TB	1 GB – 4 TB	10 GB – 100 TB
IOPS	16,000 maximum IOPS	8,000 IOPS per vCore with 200,000 maximum IOPS	327,680 IOPS with max local SSD Hyperscale is a multi-tiered architecture with caching at multiple levels. Effective IOPS depend on the workload.
Memory/vCore	5.1 GB	5.1 GB	5.1 GB or 10.2 GB4
Backups	A choice of geo-redundant, zone-redundant, or locally redundant backup storage, 1-35 day retention (default 7 days) Long term retention available up to 10 years	A choice of geo-redundant, zone-redundant, or locally redundant backup storage, 1-35 day retention (default 7 days) Long term retention available up to 10 years	A choice of locally redundant (LRS), zone-redundant (ZRS), or geo-redundant (GRS) storage 1-35 days (7 days by default) retention 2, with up to 10 years of long-term retention available 3
Availability	1 replica, no read-scale replicas, zone-redundant high availability (HA)	3 replicas, 1 read-scale replica, zone-redundant high availability (HA)	zone-redundant high availability (HA) (preview)
Pricing/billing	vCore, reserved storage, and backup storage are charged. IOPS are not charged.	vCore, reserved storage, and backup storage are charged. IOPS are not charged.	vCore for each replica and used storage are charged. IOPS are not yet charged.
Discount models	Reserved instances Azure Hybrid Benefit (not available on dev/test subscriptions) Enterprise and Pay-As-You-Go Dev/Test subscriptions	Reserved instances Azure Hybrid Benefit (not available on dev/test subscriptions) Enterprise and Pay-As-You-Go Dev/Test subscriptions	Azure Hybrid Benefit (not available on dev/test subscriptions) Enterprise and Pay-As-You-Go Dev/Test subscriptions

1 Elastic pools for Hyperscale are currently in preview. 2 Short-term backup retention for 1-35 days for Hyperscale databases is now in preview.
3 Long-term retention for Hyperscale databases is now in preview. 4 10.2 GB/vCore is available with premium-series memory optimized hardware (preview).