AWS EC2 vs Azure SQL Managed Instance

Compare AWS EC2 vs Azure SQL MI

Features

SQL Server on AWS EC2

Azure SQL Managed Instance

Deployment

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

Created via Azure portal in a VNet; a few hours to provision fully, but minimal user config (Azure sets up SQL).

Management

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

Fully managed by Azure – patching, updates, backups handled by service.

Customization

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

Restricted – cannot access OS or certain features; limited to options Azure exposes (instance size, certain settings).

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 migrating on-prem apps to Azure with minimal changes, needing instance-level features (Agent, cross-DB) but wanting a managed service.

Maintenance Responsibility

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

Microsoft – Azure automatically patches OS and SQL engine (with almost no downtime).

Operational Control

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

Partial – you have instance-level admin in SQL, but no OS access and some server-level permissions are restricted by Azure.

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: Azure performs continuous backups (point-in-time restore up to 35 days); user can initiate extra backups to storage for long-term.

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: change vCore count (online resize with brief disruption); Horizontal: limited – one primary instance, can add geo-replicas for read/DR (no multiple writable instances).

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.).

Very good for most cases: GP tier ~ “disk over network” latency (~5-10ms) and up to ~80k IOPS at max vCores, BC tier ~ “local SSD” latency (1-2ms) and up to ~320k IOPS at max size; Azure manages performance, but you might not reach extreme on-prem levels for edge cases.

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.

No auto-scale of vCores on-the-fly; you must manually scale up/down. However, you can add/remove Managed Instances in a pool (instance pools) if using that model for multi-instance elasticity, but that’s more static allocation of multiple MIs.

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 handles the version – effectively it’s the latest SQL Server engine (currently equivalent to 2019/2022). You can’t choose an older engine version, but you can set database compatibility level down to 100 (SQL 2008) for legacy 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.

Yes, one of MI’s advantages over Azure SQL DB – you can do three-part naming queries across databases on the instance, and even cross-instance via linked servers (within some constraints of managed env).

Cross-Database Queries

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

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 cannot RDP into the instance or install anything. CLR assemblies are allowed in SAFE mode within SQL (no external access), but you can’t install a custom extensibility framework or third-party utility on the server. Integration with other services must be done externally over network.

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.

Deployed into your VNet (requires a dedicated subnet)– it gets a private IP. You manage NSGs for that subnet. By default no public endpoint (optionally can enable one). It’s like a managed appliance sitting in your network.

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).

Platform-managed security: TDE on by default, backups encrypted. Azure manages OS security patches. You can use Azure AD authentication for tighter identity control. MI is deployed in your private network, adding an extra layer of isolation. It meets Azure’s compliance standards out-of-the-box (you just focus on DB-level security like user permissions).

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.

SQL Auth and Azure Active Directory Auth supported. You set an AAD admin and then you can use AAD users/groups as logins. No direct Windows AD integration (would need to sync AD to AAD). This gives centralized cloud identity management for the MI.

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).

Built-in: MI (Business Critical) has HA with automatic failover of the primary replica to a secondary if something happens (Azure handles it). General Purpose has Azure Service Fabric-based failover using remote storage. Either way, you get an SLA for HA without configuring clustering yourself.

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.

Easy DR: you can configure a geo-replica MI in another region (Auto-failover Group). This will asynchronously replicate all databases. Failover can be automatic (for groups) or manual. If you choose not to have a second MI, you still have geo-redundant backups which you could restore in another region (slower recovery).

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 MI pricing is per vCore, per hour, plus storage and backup costs. An 8 vCore General Purpose instance with 4TB follows an hourly compute + per-GB-month storage model. Business Critical costs 2-3× more per vCore due to faster hardware and extra replicas. 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 MI supports License-Included or Azure Hybrid Benefit, which lowers costs if you bring SQL Server licenses with Software Assurance. Reserved Capacity (1-3 years) offers discounts over pay-as-you-go.

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 MI in East US costs $1,700–$2,000/month ($1,300 compute + $400 storage). Hybrid Benefit can reduce compute costs by 30-40%.

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

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

A second 8-vCore MI (Auto-Failover Group) doubles the cost to $3,500–$4,000/month. If using Business Critical, an 8 vCore, 4TB instance costs $5,000+ per month, including 3 built-in replicas (no extra VM needed for HA).