SQL Server FILESTREAM: Should i use?

5 min readOct 14, 2024

Businesses are always looking for efficient ways to manage large binary files, such as images, documents, and multimedia content. SQL Server FILESTREAM provides a robust solution by allowing users to store and manage unstructured data directly in the file system while maintaining SQL Server’s transactional integrity. In this post, we’ll explore FILESTREAM, its benefits, use cases, and how it can enhance your data management strategies.

The idea for this post came from a conversation with a DBA friend. As his database grew significantly, we discussed the potential of FILESTREAM for managing large files. Let’s dive in!

What is FILESTREAM?

SQL Server FILESTREAM is a feature that allows you to store large binary data (e.g., images, videos, and documents) directly in the file system while maintaining transactional consistency with your SQL Server database. This is particularly beneficial for applications that require quick access to large binary objects (BLOBs) without the overhead of traditional SQL Server data types like VARBINARY.

As applications grow, the need to manage large amounts of unstructured data becomes paramount. FILESTREAM is designed to handle this challenge, making it ideal for applications that require extensive storage and retrieval of large files, such as content management systems, media libraries, and more.

One of the significant advantages of FILESTREAM is its seamless integration with T-SQL (Transact-SQL). Users can interact with files using familiar SQL commands, making it easy to manage both structured and unstructured data in a unified way.

FILESTREAM takes advantage of the NTFS file system, allowing for faster read and write operations on large files compared to traditional BLOB storage directly within the database.

Key Features of FILESTREAM

Integration with SQL Server: Manage BLOB data in the file system using T-SQL.
Transaction Support: Changes to FILESTREAM data are logged in SQL Server, ensuring data integrity.
Performance: Optimized for read and write operations, improving performance for large binary data.
Stream Access: Access FILESTREAM data as if it were a regular file, facilitating efficient streaming of large objects.

When to Use FILESTREAM

Large Binary Data: Ideal for applications handling large files that exceed typical database field limits.
High Throughput Requirements: Suitable for applications that frequently read and write large BLOBs, leveraging file system storage.
File System Integration: Allows interaction with files using standard file system APIs while retaining SQL Server’s transactional benefits.
Backup and Restore: FILESTREAM data can be backed up and restored alongside the database, ensuring consistency.

When Not to Use FILESTREAM

Small Data Sizes: For small binary files, using VARBINARY may be more efficient.
Complex Queries: If your application requires complex queries involving binary data, traditional database storage might be better.
Limited File System Access: If your application doesn’t need file system access, the overhead of managing permissions could be unnecessary.
Cross-Platform Compatibility: If your application must run on databases that don’t support FILESTREAM, consider traditional storage methods.

Example Use Case

Scenario: A web application that allows users to upload and share photos.

Using FILESTREAM:

Users upload high-resolution images.
Store image metadata in SQL Server and the images themselves using FILESTREAM.
Quickly retrieve and display images directly from the file system.

Not Using FILESTREAM:

For applications that only need to store small thumbnails or frequently queried images, VARBINARY may offer simpler management and better performance.

Implementation Example

Enabling FILESTREAM

Enable FILESTREAM on your SQL Server instance:
Use SQL Server Configuration Manager to enable “FILESTREAM” and specify access levels.
Create a database with FILESTREAM:

CREATE DATABASE MyDatabase
ON PRIMARY 
(NAME = MyDatabase_Data, 
 FILENAME = 'C:\Data\MyDatabase.mdf')
FILEGROUP MyFileStreamGroup CONTAINS FILESTREAM
(NAME = MyFileStream, 
 FILENAME = 'C:\Data\MyFileStream')
LOG ON 
(NAME = MyDatabase_Log, 
 FILENAME = 'C:\Data\MyDatabase.ldf');

3. Create a table to store FILESTREAM data:

CREATE TABLE MyDocuments
(
    DocumentID INT PRIMARY KEY,
    DocumentName NVARCHAR(100),
    DocumentData VARBINARY(MAX) FILESTREAM
);

4. Insert data into the table:

INSERT INTO MyDocuments (DocumentID, DocumentName, DocumentData)
VALUES (1, 'MyImage.jpg', 
(SELECT * FROM OPENROWSET(BULK 'C:\Images\MyImage.jpg', SINGLE_BLOB) AS Image));

5. Retrieve data from the table:

SELECT DocumentName, DocumentData 
FROM MyDocuments 
WHERE DocumentID = 1;

Are there better options than SQL Server FILESTREAM?

While FILESTREAM is a great option for storing large binary objects (BLOBs) in SQL Server, there are several alternatives and strategies you might consider depending on your specific requirements. Here are some options that may work better than FILESTREAM in certain scenarios:

1. External File Storage (File System):

Suitable for very large files that don’t require transactional support.
Offers better performance for read/write operations with reduced complexity.

2. Cloud Storage Solutions:

Options like Amazon S3, Azure Blob Storage, or Google Cloud Storage are excellent for applications needing scalability and global access.
Provides cost-effective storage with built-in redundancy, though it may require integration with cloud APIs.

3. NoSQL Databases:

Solutions like MongoDB, Couchbase, or Amazon DynamoDB are ideal for unstructured data and applications requiring high availability and scalability.
Designed to handle large volumes of unstructured data with flexible schemas.

4. Database Management Systems with Native BLOB Support:

PostgreSQL with Large Objects or Oracle with BFILE are alternatives for applications needing features not available in SQL Server.
These systems provide native support for large binary objects, but migration may present compatibility challenges.

Conclusion

FILESTREAM can be a powerful feature for handling large binary data efficiently while maintaining transactional support. However, it’s essential to evaluate your specific use case, considering factors like data size, access patterns, and application architecture, to determine if FILESTREAM is the right choice.
In my view, NoSQL databases often provide a more suitable alternative to SQL Server FILESTREAM. While FILESTREAM offers valuable features for certain use cases, NoSQL databases may provide a more adaptable, scalable, and performant solution for applications dealing with large volumes of unstructured data. Depending on your specific needs, considering NoSQL could lead to more efficient data management and application development.