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Database & Data Management · head to head

Cassandra vs Microsoft SQL Server

Cassandra logo

Cassandra

Database & Data Management

Manage massive amounts of data with linear scalability

From
Free
Rated
-
Full reviewWebsite
Microsoft SQL Server logo

Microsoft SQL Server

Database & Data Management

Enterprise-grade relational database management system

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Cassandra no support for joins across tables; Microsoft SQL Server licensing and on-premises deployment costs are high compared to open-source alternatives, with Enterprise Edition exceeding $60,000 for minimum core requirements
  • They diverge on capability: Cassandra covers Linear Scalability, Microsoft SQL Server covers T-SQL.

Where they differ

Only the attributes on which Cassandra and Microsoft SQL Server actually diverge.

Attributes where Cassandra and Microsoft SQL Server differ
AttributeCassandraMicrosoft SQL Server
PlatformsLinux, macOS, Windows, Docker, KubernetesWindows Server, Linux (RHEL, SUSE, Ubuntu), Docker, Azure
Founded20081989

Identical on both: starting price (Free), pricing model (Unknown), free tier (Yes), user rating (Not yet rated), category (Database & Data Management).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Cassandra

  • Linear Scalability
  • Fault Tolerance
  • Multi-datacenter Replication
  • Tunable Consistency
  • CQL Query Language
  • Distributed Architecture
  • No Single Point of Failure
  • DataStax

Only in Microsoft SQL Server

  • T-SQL
  • ACID Compliance
  • Advanced Security
  • In-memory OLTP
  • Columnstore Indexes
  • Always On Availability
  • Machine Learning Services
  • Azure

Both cover

  • Linux support
  • Windows support
  • Docker support

What people use each for

The jobs each tool is most often brought in to do.

Cassandra

  • Real-time applicationsnot Microsoft SQL Server
  • Content managementnot Microsoft SQL Server
  • User profilesnot Microsoft SQL Server
  • Mobile backendsnot Microsoft SQL Server
  • Cachingnot Microsoft SQL Server

Microsoft SQL Server

  • Transaction processingnot Cassandra
  • Data storagenot Cassandra
  • Application backendnot Cassandra
  • Reportingnot Cassandra
  • Data analyticsnot Cassandra

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Cassandra

  • No support for joins across tables
  • No ACID transactions across multiple rows
  • Data model must be designed around query patterns upfront, making schema evolution difficult
  • Partition key misconfigurations can cause uneven data distribution and hotspots that degrade performance

Microsoft SQL Server

  • Licensing and on-premises deployment costs are high compared to open-source alternatives, with Enterprise Edition exceeding $60,000 for minimum core requirements
  • Performance monitoring toolset is insufficient for hybrid cloud environments requiring real-time analytics across multiple deployment types
  • Heavy I/O resource consumption can saturate disk volumes and degrade performance when processing large transaction workloads
  • Always On availability groups with up to 8 secondary replicas are limited to Enterprise edition only; Standard supports only basic availability groups with 2 replicas
  • CPU and memory scaling is capped at 4 sockets or 32 cores on Standard edition, limiting deployments requiring higher compute capacity

Pricing, plan by plan

Cassandra

Free

No published plan breakdown. See the Cassandra review.

Microsoft SQL Server

Free
  • ExpressFree
    • 4 cores maximum
    • 1.4 GB memory per instance
    • 50 GB database size limit
  • DeveloperFree
    • All Enterprise features
    • Non-production use only
  • Standard$3945/per 2-core pack
    • 32 core maximum per instance
    • 256 GB buffer pool memory
    • Basic availability groups with 2 replicas
  • Enterprise$15123/per 2-core pack
    • Unlimited scaling
    • Always On with up to 8 secondaries
    • Advanced security and HA features

Which should you pick?

Choose Cassandra if

  • You need linear scalability.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker, Kubernetes.
  • You also want fault tolerance.
Cassandra review

Choose Microsoft SQL Server if

  • You need t-sql.
  • You want to start without paying.
  • You work on Windows Server, Linux (RHEL, SUSE, Ubuntu), Docker, Azure.
  • You also want acid compliance.
Microsoft SQL Server review

Questions people ask

Is Cassandra or Microsoft SQL Server better?
Neither clearly leads. Cassandra starts at Free and Microsoft SQL Server at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cassandra or Microsoft SQL Server?
Cassandra starts at Free and Microsoft SQL Server at Free.
Does Cassandra or Microsoft SQL Server run on more platforms?
Cassandra runs on Linux, macOS, Windows, Docker, Kubernetes. Microsoft SQL Server runs on Windows Server, Linux (RHEL, SUSE, Ubuntu), Docker, Azure.
Can I use Cassandra for free?
Both have a free tier, so you can try either at no cost before committing.
What is Cassandra best used for?
Cassandra is most often used for real-time applications, content management, user profiles, mobile backends. Of those, real-time applications and content management are not what Microsoft SQL Server is typically brought in for.
What can Cassandra do that Microsoft SQL Server cannot?
Cassandra covers Linear Scalability, Fault Tolerance, Multi-datacenter Replication, Tunable Consistency. Microsoft SQL Server covers T-SQL, ACID Compliance, Advanced Security, In-memory OLTP. Both handle Linux support, Windows support, Docker support.

Answered from the vendors’ own pages

Cassandra: Does Cassandra support joins between tables?

No. Cassandra does not support joins or foreign keys. The data model requires denormalization, meaning data must be duplicated across tables to support different query patterns.

Source
Microsoft SQL Server: What is the pricing model for SQL Server?

SQL Server uses core-based licensing with per-2-core pack pricing. Enterprise Edition costs approximately $15,123 per 2-core pack (minimum 8 cores). Standard Edition costs approximately $3,945 per 2-core pack. Developer and Express editions are free. Software Assurance adds 25-35% annually for upgrades and support.

Source
Cassandra: Does Cassandra offer ACID transactions?

No. Cassandra provides only row-level atomicity and isolation, not full ACID transactions across multiple rows or tables. It uses lightweight transactions via Paxos for per-row compare-and-set operations.

Source
Microsoft SQL Server: Does SQL Server run on Linux?

Yes. SQL Server 2017 and later run on Linux (Red Hat Enterprise Linux, SUSE Linux Enterprise Server, Ubuntu), Docker containers, and Windows with feature parity including Always On availability groups, Active Directory authentication, and encryption.

Source
Cassandra: What programming languages can connect to Cassandra?

Cassandra supports official drivers for multiple languages including Python, Java, Node.js, and Go, allowing applications to communicate via the native Cassandra protocol.

Source
Microsoft SQL Server: Is there a free edition of SQL Server?

Yes. SQL Server Express is free and includes all functionality of Enterprise edition for development and testing, with limits of 4 cores, 1,410 MB memory per instance, and 50 GB per database. Developer edition is also free for non-production use.

Source
Cassandra: Can I deploy Cassandra in the cloud?

Yes. Cassandra can run on any cloud platform (AWS, Google Cloud, Azure) via Docker, virtual machines, or managed services like DataStax Astra DB, which provides a fully managed DBaaS option.

Source
Microsoft SQL Server: Can SQL Server be deployed offline?

Yes. SQL Server can be installed from offline media on machines without internet access. Microsoft provides complete offline installation packages for SQL Server, SSMS, and supporting components, making deployment in isolated or air-gapped environments feasible.

Source
Cassandra: Does Cassandra have a free option?

The open source Apache Cassandra is free. DataStax also offers Astra DB with a free tier providing up to 25GB storage and 25 million read/write operations per month.

Source
Microsoft SQL Server: What high availability options does SQL Server provide?

SQL Server offers Always On availability groups (Enterprise only), Always On failover cluster instances, database mirroring, log shipping, and for disaster recovery, failover servers in Azure and Accelerated Database Recovery for faster recovery after failures.

Source
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