NTFS and ReFS limitations

Question

As far as I know, by design NTFS supports partitions containing up to 2^64 clusters. But NTFS implementation in Windows XP and later is somewhat limited by Windows stack which can address 2^32 clusters only, thus limiting effective partition size to 256 TB (when using 64 KB clusters).

Questions:

1. Why theoretical NTFS partition limitation is 16 EB only as stated by many sources on the Internet? 2^64 is much bigger than this.
2. If 256 TB limitation was due to Windows stack limits on 32 bit versions of Windows, why on 64 bit versions of Windows we cannot have partitions up to designed NTFS limitation of 2^64*65536 bytes?
3. And ReFS: According to Microsoft, its design limitation is 2^78 clusters with 16 KB clusters. Why only 16 KB? I can format partitions using ReFS and 64 KB clusters (in Windows Server 2012 R2).
4. Is there any support of ReFS on Windows Server 2008 R2?

Answer 1

Its important to understand that ReFS is designed for storing large amounts of data. NTFS just is not up to the job of dealing with large data sets. As a next generation file system, ReFS still cannot be booted from, and lacks some features of NTFS such as EFS and HardLinks just to name two.

1.Why theoretical NTFS partition limitation is 16 EB only as stated by many sources on the Internet? 2^64 is much bigger than this.

NTFS is a pretty old file system developed when a 2GB Hard Drive was a big deal. It's old, like over twenty years old.

2.If 256 TB limitation was due to Windows stack limits on 32 bit versions of Windows, why on 64 bit versions of Windows we cannot have partitions up to designed NTFS limitation of 2^64*65536 bytes?

Like I said, NTFS is from the Windows 2000 era, it predates WindowsXP which is being taken out to pasture here soon anyway. It's old.

3.And ReFS: According to Microsoft, its design limitation is 2^78 clusters with 16 KB clusters. Why only 16 KB? I can format partitions using ReFS and 64 KB clusters (in Windows Server 2012 R2).

ReFS is evolving, that may have been the limit at some point, but now it's possible

4.Is there any support of ReFS on Windows Server 2008 R2?

Prolly not, that's one of the reasons ReFS adoption has been slow.This is how Microsoft makes money, the new bells and whistles cost money, you want the new feature? Pay up and upgrade.

See Also:

http://en.wikipedia.org/wiki/NTFS

http://en.wikipedia.org/wiki/ReFS

http://blogs.technet.com/b/askpfeplat/archive/2013/01/02/windows-server-2012-does-refs-replace-ntfs-when-should-i-use-it.aspx