What is Microsoft OneLake? The Unified Data Lake for the Microsoft Fabric Era

Introduction

In today’s fragmented data landscape, organizations often find themselves juggling multiple data lakes, warehouses, and silos, each managed by different teams or serving different data analytics engines. This complexity slows down time to insight, increases storage costs, and undermines data governance and data consistency.

Enter Microsoft OneLake, the new unified data lake that serves as the foundation of the Microsoft Fabric platform. It’s Microsoft’s vision of “OneDrive for data”; a single, logical data lake for the entire organization, regardless of data domains, tools, or user personas.

In this blog, we’ll unpack what OneLake is, how it works within the Microsoft ecosystem, and how it compares to traditional data lakes and lakehouses. Whether you're a data engineer, analyst, or architect, this post will help you understand how Fabric OneLake reshapes modern data infrastructure.

What is Microsoft OneLake?

Microsoft OneLake is a multi-cloud, single logical data lake designed to unify all organizational data across teams and services. It is built on Azure Data Lake Storage Gen2 (ADLS Gen2) but is presented as a logical, organization-wide data lake, not a collection of individual storage accounts.

OneLake is a core part of Microsoft Fabric, the all-in-one analytics solution that brings together Power BI, Azure Synapse Analytics, Data Factory, and other services under one integrated platform. While each Fabric engine handles its own workloads (BI, warehousing, ML, pipelines), OneLake is the shared, central data layer that connects them all.

This architecture is designed to eliminate the need for ETL between Fabric services. With DirectLake technology, tools like Power BI can query Delta Lake tables in OneLake directly, bypassing traditional import processes entirely.

Core Features of Microsoft OneLake

Unified Storage Architecture

All Fabric services use OneLake by default. Instead of managing multiple data lakes across departments or regions, organizations can store their data in one logical namespace with unified governance, access controls, and format support.

Shortcut-Based Virtualization

OneLake supports shortcuts, which let you reference data stored in other storage systems (including Amazon S3, ADLS Gen2, and other OneLake locations) without copying it. This minimizes data duplication and simplifies cross-team access.

Delta Format as a First-Class Citizen

OneLake natively supports Delta Lake format, ensuring compatibility with ACID transactions, schema evolution, and time travel. This is essential for data engineering and analytics use cases.

Security and Governance

Integration with Microsoft Purview provides built-in data discovery, classification, and lineage. Access controls are managed centrally, with workspace-level permissions and Microsoft Entra ID (formerly Azure AD).

Multi-Engine Access

OneLake supports concurrent access from Fabric’s Synapse Data Warehouse, Power BI, Data Science notebooks, and Data Factory, all with zero-copy architecture.

OneLake vs Traditional Data Lakes

OneLake and the Microsoft Fabric Ecosystem

OneLake isn't just a standalone storage layer, it’s the foundational substrate of Microsoft Fabric. Here’s how it ties into each component:

• Power BI (DirectLake Mode): Power BI datasets can now query Delta tables in OneLake directly, skipping import and dataset refreshes. This enables real-time dashboards with massive performance improvements.

• Synapse Data Warehouse: Tables in Synapse are stored as Delta Lake files inside OneLake, giving warehouse users lakehouse-style flexibility with transactional integrity.

• Data Factory Pipelines: ETL and ELT pipelines in Fabric’s Data Factory natively read from and write to OneLake, eliminating complex staging steps.

• Data Science & ML Workloads: Fabric notebooks access OneLake as their default file system, allowing data scientists to train models directly on the same datasets used by business intelligence and engineering teams.
  
  

Benefits for Data Engineers & Analysts

For Data Engineers

• Eliminate Redundant ETL: With OneLake serving as the default storage layer across Fabric, engineers no longer need to shuttle data between services. A dataset loaded for ML is instantly available to Power BI and Synapse.

• Built-in Delta Support: Delta Lake simplifies job orchestration, schema evolution, and rollbacks, enabling more robust pipelines.

• Faster Time-to-Delivery: Integrating with OneLake’s shortcut feature allows engineers to make external datasets immediately accessible without loading or transforming them again.

For Data Analysts

• DirectLake = Real-Time Dashboards: No need to wait for dataset refreshes. Analysts can build dashboards in Power BI directly on Delta tables stored in OneLake.

• Self-Service Data Discovery: Integration with Microsoft Purview helps analysts understand data lineage, ownership, and classifications without needing a data engineer’s help.

• Single View Across Teams: Analysts can access sales, marketing, product, and finance data, all under a unified namespace with consistent naming and governance.

Use Cases of OneLake in Action

Retail

A large retailer manages inventory, POS, and customer loyalty data. Instead of loading these datasets into separate systems for BI, ML, and operations, all teams consume data from OneLake.
Real-time sales dashboards use DirectLake, while marketing teams build ML models for customer segmentation from the same data.

Healthcare

A hospital system maintains patient records, lab results, and billing data. Using OneLake shortcuts, clinical data from on-prem systems and cloud partners is federated without moving the data.
Data scientists build diagnostic prediction models in notebooks, and administrators use Power BI for operational reports, all on the same data.

Finance

A fintech company logs transactions from mobile apps, fraud systems, and KYC platforms. With OneLake, these datasets are stored once and accessed by compliance teams, fraud analytics, and CFO dashboards, without duplicating storage.

How OneLake Fits into the Modern Data Stack

OneLake Pricing Overview

OneLake itself is not priced as a separate SKU. Instead, it is built on top of Azure Data Lake Storage Gen2, and charges are based on:

• Storage used (per GB per month)

• Data access (read/write operations)

• Networking (egress costs if applicable)

The true cost consideration comes from Fabric compute engines (Synapse, Power BI, Data Factory), not the OneLake layer. However, by consolidating storage and reducing data duplication, OneLake lowers total cost of ownership (TCO) compared to traditional, siloed architectures.

How Integrate.io Fits Into This Picture

While OneLake provides a powerful centralized architecture within Microsoft Fabric, getting your data there is often the biggest barrier. That’s where Integrate.io delivers value as a data integration platform purpose-built to support modern lakehouse destinations like OneLake.

Ingest Data From Any Source

Integrate.io helps teams extract, transform, and load data from hundreds of sources, SaaS apps, SQL/NoSQL databases, cloud platforms, into OneLake with ease. Whether it’s Salesforce, MongoDB, or NetSuite, you can bring that data into your Microsoft Fabric environment without custom code or manual scripting.

Built for Low-Code, High-Agility Teams

Use a visual, no-code interface to build robust ETL and ELT pipelines that load data directly into Delta Lake format inside OneLake. This speeds up implementation, reduces dependency on engineering, and accelerates analytics.

Enhance Governance, Quality, and Compliance

With built-in encryption, logging, scheduling, and monitoring, Integrate.io helps data teams stay compliant with regulations like HIPAA and SOC 2, especially important when loading sensitive or regulated data into OneLake.

Bridge the Gap Between Systems

While OneLake optimizes everything inside Microsoft Fabric, Integrate.io ensures a smooth and reliable data flow into that ecosystem.

Want to see how fast you can bring your external data into Microsoft OneLake?

Start your free trial of Integrate.io and get data pipelines live in hours, not weeks.

Conclusion

Microsoft OneLake is more than just a new storage layer, it’s a strategic shift toward a unified, governed, and integrated data foundation for the entire organization. By removing silos, supporting open formats, and integrating natively with every Fabric service, OneLake redefines what’s possible with analytics on Azure.

Whether you’re streamlining ETL pipelines, enabling self-service BI, or building ML workflows, OneLake ensures everyone works from the same source of truth, with fewer tools, less friction, and better governance.

Looking to connect your data sources to OneLake quickly and securely?

Start a free trial of Integrate.io and see how easy it is to build scalable pipelines into Microsoft Fabric.

FAQs About Microsoft OneLake

1. Is Microsoft OneLake the same as Azure Data Lake Storage (ADLS)?

No. Microsoft OneLake is built on top of ADLS Gen2 but provides a logical, unified data lake experience across all Microsoft Fabric services. While ADLS is the underlying storage engine, OneLake introduces higher-level features like shortcuts, workspace-based governance, and native integration with tools like Power BI, Synapse, and Data Factory.

2. Can I use OneLake without Microsoft Fabric?

No. OneLake is tightly integrated into the Microsoft Fabric ecosystem and is not offered as a standalone product. It serves as the default storage layer for all Fabric workloads, such as Synapse Data Warehouse, Power BI (via DirectLake), and Data Factory pipelines.

3. How do I move external SaaS or database data into OneLake?

Microsoft Fabric currently has limited native connectors for external sources for data movement. The most efficient way to move data into OneLake is by using an ETL platform like Integrate.io, which offers prebuilt connectors and visual pipelines to load data into Delta format inside OneLake, quickly, securely, and without manual coding.