Opal vs Armadillo

Datashield in the wild

What They Are

Opal:

• Mature platform by OBiBa
• Full data management: storage, harmonisation, metadata, cataloguing
• Widely used in DataSHIELD documentation and consortia

Armadillo:

• Lightweight server by MOLGENIS team (Support & Development)
• Built specifically for DataSHIELD federated analysis
• Easier deployment, fewer dependencies

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Architecture & Storage

Opal

• Uses relational DBs (MySQL, PostgreSQL, MariaDB) or MongoDB
• Stores data and metadata in databases
• Supports complex workflows

Armadillo

• Stores data on the filesystem (e.g., Parquet files)
• Uploads via UI or R package
• Simpler, less infrastructure heavy

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Features

Opal

• Rich functionality: harmonisation, metadata, cataloguing
• Multiple R servers, horizontal scaling
• Advanced admin and access control

Armadillo

• Focused on core federated analysis features
• Profiles: named/versioned DS package collections
• Permissions and function whitelisting
• Lightweight and user-friendly

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Pros & Cons

Opal

✅ Mature and feature-rich ✅ Good for large, complex infrastructures ❌ Higher complexity and overhead

Armadillo

✅ Lightweight, quick to deploy ✅ Easier for cohorts with modest resources ❌ Fewer features (e.g., less advanced harmonisation) ❌ Newer, still catching up in some areas

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When to Use

Choose Opal if:

• You need full data management, metadata, and harmonisation
• You operate in a large consortium with complex workflows

Choose Armadillo if:

• You want lightweight, easy deployment
• You mainly need secure federated analysis
• Your team has limited IT resources and wants Molgenis Support

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