Is NTFS 16 TB volume size limit "real"?
In Windows 2003, 232-1 clusters. With 64k clusters = 256TB
With full 264-1 sizing, 256 TB * 256 TB
21 TB is a rounding error, quite frankly
Did you check your facts before posting?
Aside from technical limitations, handling such a huge volume would be quite impractical.
Just think about what would happen if you ever had to CHKDSK it.
I just threw a 22TB LUN at one of my spare W2K3 servers, created it as GPT disk and chose 64K clusters - formatted it no problem at all, I then filled it up and deleted the content - no problems :)