File Servers
Lesson 4


By Sai Kurada
August 31, 2023
ReFS, or Resilient File System, is a file system developed by Microsoft for use in Windows operating systems. It is designed to provide enhanced reliability, scalability, and performance for managing large amounts of data.
Goals of ReFS:

· Resilience: ReFS is designed to be highly resilient to data corruption and to provide mechanisms for detecting and repairing issues.
· Scalability: It is optimized for handling large amounts of data and very large volumes.
· Data Integrity: ReFS employs various techniques to maintain data integrity and to prevent common forms of data corruption.
· Compatibility: It can be used alongside NTFS (the more established file system for Windows) and supports a wide range of features and APIs.

Key Features:

· Integrity Streams: ReFS uses checksums to verify data integrity. This means that it can detect when data is corrupted and, if a redundant copy is available, can automatically correct it.
· Data Scrubbing: ReFS periodically reads all the data on the volume and verifies its integrity. If any issues are detected, it attempts to correct them.
· Sparse File Support: ReFS can efficiently handle large files with significant amounts of empty space. This is useful for scenarios like virtual machine storage.
· Efficient Copy on Write: ReFS uses a copy-on-write approach, which means that when a file is modified, the original data is preserved until the new data is successfully written.
· Resilient to Power Failures: ReFS is designed to handle power failures and other types of system crashes without compromising data integrity.
· Scalability: It supports extremely large file sizes and volumes, which is important for enterprise-level storage needs.
· No Need for Chkdsk: ReFS does not require regular CHKDSK (Check Disk) scans like NTFS does. CHKDSK is a utility in Windows that checks and repairs file system errors.


· Lack of Some NTFS Features: ReFS does not support all the features of NTFS, such as compression, file-level encryption (EFS), and disk quotas.
· Not Bootable: ReFS cannot be used as the boot partition on a system drive. It's primarily used for data volumes.
· Not Suitable for All Scenarios: While ReFS excels in scenarios where data integrity is of paramount importance, NTFS may still be the better choice for certain applications.

Use Cases:

· ReFS is well-suited for environments where data integrity is critical, such as in enterprise storage solutions, file servers, and backup systems.
· It is commonly used in conjunction with Storage Spaces, which is a technology in Windows Server for managing and virtualizing storage.
· ReFS is often used in scenarios where large amounts of data need to be stored reliably, such as in data centers and cloud environments.

ReFS is available in certain editions of Windows Server and Windows 10/11, but it's primarily targeted at enterprise environments due to its advanced features and scalability capabilities.