AWS EC2 vs Azure SQL DB

Compare Amazon EC2 vs Azure SQL Database

Features

SQL Server on AWS EC2

Azure SQL Database

Deployment

User deploys an EC2 VM and installs SQL (AWS provides pre-built SQL AMIs)– faster than on-prem, but manual SQL config required.

Instant provisioning of a database via portal/CLI – ready in minutes, no VM or OS to manage (fully platform-managed).

Management

Fully self-managed: you handle OS/SQL patches, backups, monitoring.

Fully managed by Azure – Microsoft handles all patching and maintenance.

Customization

Maximum – full OS control, any SQL version/settings, install any software.

Very restricted – no OS or instance access, only DB-scoped settings; cannot use unsupported features (e.g., CLR, xp_cmdshell).

Use Case

When full control is needed in AWS (e.g., custom configurations or unsupported features) ; lift-and-shift with minimal cloud modifications.

Best for new cloud-native apps, SaaS, and scenarios requiring zero infrastructure management – modern applications that can live within one DB (or use sharding/pools).

Maintenance Responsibility

You/your DBAs – AWS doesn’t patch your EC2 instances or SQL (user schedules and applies updates).

Microsoft – fully automatic patch management and updates (you don’t even see it happening).

Operational Control

Full sysadmin rights on SQL and admin on OS – complete freedom (and responsibility).

Partial – you have db_owner on your databases and a contained “server” admin, but many instance-level features aren’t available (no control over master/tempdb beyond some settings).

Backups

Must be set up by user (e.g., backup to S3 or EBS, or use AWS Backup service); automated backup = none by default.

Automated: full PITR backups are done by Azure (e.g., every 5-10 min log backups); long-term retention can be configured for weekly/monthly/yearly backups.

Scalability

Vertical: change EC2 instance type (manual, downtime); Horizontal: add more VMs and configure clustering or load splitting manually (no built-in auto-scale).

Vertical: move between DTU/vCore tiers easily (some operations online); Horizontal: scale out by sharding or using multiple databases (Elastic Pool), or use readable geo-replicas – not transparent sharding, app must handle if needed.

Performance

Can be very high (depends on instance and EBS setup): e.g., EC2 with Provisioned IOPS SSD can hit tens of thousands of IOPS; you can tune everything (Storage cache, TempDB on instance store, etc.).

Excellent for typical workloads, with options to choose higher tiers if needed: Business Critical has low-latency SSD and 2-4 replicas for read, Hyperscale can scale out readers and handle very large DBs. The platform handles tuning, but you might sacrifice some extreme tuning (e.g., can’t control file placement).

Elasticity

No native auto-scaling – fixed resources unless manually changed; you’d need custom scripts or AWS Auto Scaling Groups (not typical for DB VMs) to simulate elasticity.

Yes (Serverless option) – Azure SQL DB serverless will auto-scale CPU/RAM within set bounds and even pause the DB on inactivity, providing true on-demand elasticity. For provisioned databases, you can scale with an API call (not automatic, but quick) and use Azure Automation to schedule or trigger it.

SQL Server Version

Any version you want (you install it). AWS SQL AMIs typically offer 2016–2019 and now 2022, but you could install an older one manually if needed (not recommended, but possible).

Azure SQL Database always runs the latest stable SQL Server engine managed by Microsoft. It doesn’t match a specific legacy version but supports compatibility levels up to 160 (SQL 2022) for older T-SQL compatibility.

SQL Feature Support

All features supported – it’s a full SQL Server. (If Windows, features like SSRS/SSAS need separate installation but can be on the same VM or another.) No artificial restrictions – you can even enable unsupported stuff at your own risk.

Azure SQL DB supports most SQL features but lacks SQL Agent, CLR assemblies, FILESTREAM, and cross-database transactions. Features like JSON, Full-Text Search, In-Memory OLTP, and Temporal Tables are fully supported.

Cross-Database Queries

Yes, you can query across DBs on the same instance or use linked servers between instances – same as normal SQL.

No (not directly): each Azure SQL DB is isolated. Cross-DB joins require external tables or client-side join logic. Azure provides elastic query which is essentially a workaround (create external data source to another DB). So it’s not as seamless as on a full instance.

Custom Software

Yes – install anything on the VM (e.g., anti-virus, monitoring agents, custom CLR assemblies in SQL, etc.). You have OS access to do so.

No – you get only the database environment. If you need something like a specialized full-text extender or a custom compression DLL, you can’t install that on Azure SQL DB. You’d have to move to MI or VM if installation is required.

Network Configuration

Runs in AWS VPC – you control subnet placement, security groups, routing (it’s like any other VM). You can give it a public IP or keep it private. It integrates with on-prem via VPN/Direct Connect seamlessly.

By default, accessible over the internet with a secure endpoint (you restrict by firewall rules). If needed, use Private Link to bring it into your VNet with a private IP. You don’t see or manage the underlying network, but you can control connectivity at a high level (public/private).

Security

You manage security: enable TDE if needed (with your own key or certificate), use AWS KMS for volume encryption (just a checkbox on EBS), configure Windows Firewall or AWS Security Groups. Compliance depends on your configuration – AWS provides baseline (e.g., you can use AWS Config/Audits, but it’s on you to implement security best practices).

Azure SQL DB enforces TDE for data at rest, encrypted connections, and compliance with PCI DSS, HIPAA, etc. Auditing and Advanced Threat Protection enhance security, while Private Link restricts network access. As a multi-tenant service, OS-level access is not available, but Microsoft ensures data isolation and certification compliance.

Authentication

Windows Auth (AD) and SQL Auth both supported – it’s just a normal SQL Server in a Windows environment. You’d typically join the EC2 to your domain to use integrated auth.

Supports SQL authentication and Azure AD authentication, allowing Azure AD users to log in with modern identity management and MFA. Traditional Windows AD accounts require syncing to Azure AD for authentication.

High Availability

Must be configured by user (e.g., Always On AG across two EC2s in different AZs). EC2 itself can be put in an Auto-Recovery, but that’s infrastructure-level. True HA = you set up clustering or AG, which is complex but doable (Launch Wizard can assist).

Azure SQL DB provides built-in HA with at least three replicas: General Purpose uses Azure storage redundancy, while Business Critical employs a 3-4 node Always On quorum with 99.99% SLA. Failovers are automatic with minimal impact.

Disaster Recovery

User-defined: e.g., set up an async AG to a second region’s EC2, or do periodic backups to an offsite location and plan for restore. AWS doesn’t automatically replicate EC2-based SQL to another region – you must architect it.

Supports Active Geo-Replication with up to 4 readable replicas in different regions. Failover can be manual or automated via Auto-Failover Groups. If not configured, point-in-time restore to another region serves as a DR option.

Pricing

Pay for EC2 VM + storage + bandwidth. E.g., $2.0k/month for an 8vCPU VM with SQL Std license. If BYOL, you pay cloud costs ($700) and use your own license (~$1.3k amortized) separately. Reserved Instances can cut EC2 cost ~30-50%.

Azure SQL DB pricing is based on compute (vCores or DTUs) and storage. An 8 vCore General Purpose database with 4TB costs ~$1,800/month, while Business Critical is 2-3× higher due to extra replicas and SSDs. Hyperscale storage is charged per GB, but compute is similar to General Purpose. SQL licensing is included.

Licensing Model

License-Included or BYOL. Can use on-demand hourly (with Windows/SQL licensing bundled) or bring your own licenses (requires Software Assurance for mobility). BYOL on EC2 can run on Dedicated Hosts or via License Mobility on shared tenancy.

Azure SQL DB follows a license-included model, but Azure Hybrid Benefit reduces costs if you bring existing licenses. Billing is pay-as-you-go or reserved capacity (1-3 years). There are no CALs, and Enterprise Edition (SA) holders get cost breaks on Business Critical.

Pricing Comparison of Database Configuration

8vCore + 4TB Data size + Backup,  Single Instance

~$2,000/month (license-included Std) for m5.2xlarge + 4TB gp3 on AWS.
BYOL could lower cost if you already own a license.
On-prem roughly equivalent ~$1k (Std) to $3k (Ent) when amortized, but cloud includes hardware + management overhead.

An 8 vCore, 4TB General Purpose Azure SQL DB costs ~$1,800/month ($1,400 compute + $400 storage).
Switching to Business Critical raises the price to $4,000–$5,000/month. Hybrid Benefit can cut vCore costs by ~40%.

8vCore + 4TB Data size + Backup + DR/HA

EC2: ~$4,000/month for two instances (Multi-AZ).

HA is included at no extra cost. For DR, a geo-replicated secondary (8 vCore GP instance) adds ~$1,800/month, bringing total costs to $3,600/month.
Auto-Failover Groups require paying for both primary & secondary. Business Critical geo-secondaries cost the full BC rate.