not getting full storage size when striping?

[Carlos D]

I'm trying to setup my 2 x 6tb drives and noticed that when creating the volume it's only giving me 10.91tb.

What is taking the remaining 1.09tb? Just wondering if that's normal or it's because something's wrong.. I understand raid probably needs to use a portion of the storage but I thought that it would be way less than 1tb..

Screenshot attached

 

[m0nkey_]

A 6TB drive won't actually be 6TB. It's measured by the International Standard of Units (SI), making 1000kB = 1024KiB. So a 6TB hard drive will be approximately 5.5TB in size, resulting in nearly 11TB of usable space, or in your case 10.91TB.

https://en.wikipedia.org/wiki/Kilobyte

 

[SweetAndLow]

Perfectly normal, same thing happens in windows also. hdd manufactures use 1000 to do their math and computers use 1024 to do their math and that causes the numbers to not match.

 

[pasiz]

A 6TB drive won't actually be 6TB. It's measured by the International Standard of Units (SI), making 1000kB = 1024KiB. So a 6TB hard drive will be approximately 5.5TB in size, resulting in nearly 11TB of usable space, or in your case 10.91TB.

https://en.wikipedia.org/wiki/Kilobyte

6TB drive is actually 6 TeraBytes (TB). 10.91 TebiBytes (TiB) is 12 TeraBytes (TB). 12 Terabytes is 12*10^12 Bytes.
So you have real space of 12000000000000 Bytes, binary counting model is really annoying and confusing, if you write million bytes to disk, your filesystem says that you have 0.953 MiB (in windows it's reported MB), so doing math is really hard. You can use df -H to see with SI units...