ReFS Quirks

• In ReFS the cluster size is always equal to 64 KB, and the size of the filesystem metadata page is always 16 KB.
• ReFS does not have resident files.
• ReFS designers recommend using the filesystem on a mirrored storage which means that many features are available only on a mirrored system.

Because of all this, the overhead in ReFS is significantly larger than that in NTFS. For non-resident files average overhead in NTFS for typical configurations is 2 KB per file, for large volumes (16 TB and more) - 8 KB per file. In ReFS the average overhead is always 32 KB per file.