ReFS was designed to overcome problems that had become significant over the years since NTFS was conceived, which are related to how data storage requirements have changed.
The key design advantages of ReFS include automatic integrity checking and data scrubbing, elimination of the need for running chkdsk, protection against data degradation, built-in handling of hard disk drive failure and redundancy, integration of RAID functionality, a switch to copy/allocate on write for data and metadata updates, handling of very long paths and filenames, and storage virtualization and pooling, including almost arbitrarily sized logical volumes (unrelated to the physical sizes of the used drives).
As a result of built-in resiliency, administrators do not need to periodically run error-checking tools such as CHKDSK when using ReFS.
[4] Support for alternate data streams and hard links was initially not implemented in ReFS.
[13] ReFS had initially been unsuitable for Microsoft SQL Server instance allocation due to the absence of alternate data streams.
[3] The initial versions removed some NTFS features, such as disk quotas, alternate data streams, and extended attributes.
This is particularly needed for virtualization, and is stated to allow fast provisioning, diff merging, and tiering.
[3] Windows Insider Preview 22H2 and 23H2 (builds 226** and 25***) support ReFS volume compression using LZ4 and zstd algorithms.
The version, cluster size and other features of the filesystem can be queried with the command fsutil fsinfo refsinfo volumename.
At the time, their features were similar, with both supporting checksums, RAID-like use of multiple disks, and error correction.
As of November 2019[update], Microsoft has not published any specifications for ReFS, nor have any working open-source drivers been made.