Help, problem with total storage count

[edomacri]

Hi there,
i've been recently updated from 9.3 to 9.10 with a fresh install, but while setting up the new version I hooked up that in my RAIDZ1 (Raid 5) setup there is somthing wrong.
I have a 4x1TB HDDs in a DELL CS24-NV7. The total storage should be aprox. 3TB (and it shows in /mnt) but in Storage section says that are available 3.1TB and I can use only 2TB which 20% is already occupied. (as you can see in pictures). What can I do to get all 3TB?

 

[enemy85]

there is nothing wrong with your setup...
you have 4x1TB raw space (equal to 3.6TiB approx) -> FIRST LINE archivio 3TB
you have 3x1TB net space after raidz1 parity (equal to 2.6-2.7TiB approx) -> SECOND LINE
if you add the used space to the available one you see that match

 

[edomacri]

@enemy85

there is nothing wrong with your setup...
you have 4x1TB raw space (equal to 3.6TiB approx) -> FIRST LINE archivio 3TB
you have 3x1TB net space after raidz1 parity (equal to 2.6-2.7TiB approx) -> SECOND LINE
if you add the used space to the available one you see that match

As you say

4x1TB raw space (equal to 3.6TiB approx)

but it shows 3.1 TiB of RAW space instead of 3.6 TiB
and

you have 3x1TB net space after raidz1 parity (equal to 2.6-2.7TiB approx)

it shows 2.0 TiB of NET space instead of 2.7 TiB...
I can't understand why this...

 

[enemy85]

3.1 free + 0.5 used =3.6
2 free + 0.6 used =2.6

 

[danb35]

but it shows 3.1 TiB of RAW space

No, it doesn't. It shows 3.1 TiB available. Available space is the space that isn't being used--put differently, it's the free space.