Seem to be missing space on newly installed drive

[NebulaM57]

Hello,

System Info:
Build FreeNAS-8.3.0-RELEASE-x64 (r12701M)
Platform AMD Phenom(tm) 9600 Quad-Core Processor
Memory 3951MB

System runs great with 2 500GB UFS drives currently installed... no RAID.

I just installed an additional 3TB drive into the system, UFS mode. No RAID. Just using as straight drive space. Made sure there were no existing partitions on the drive before hand. Drive installed as expected via Volume Manager (fn03). I've applied the permissions and created an CIFS share and have access via Windows 7. Active Volumes window shows:

fn01 /mnt/fn01 380.3 GiB (91%) 39.6 GiB 456.5 GiB HEALTHY
fn02 /mnt/fn02 248.2 GiB (62%) 171.8 GiB 456.5 GiB HEALTHY
fn03 /mnt/fn03 8.0 KiB (8%) 2.5 TiB 2.7 TiB HEALTHY

Upon checking drive in Windows, it shows Used space of 236GB with nothing on the drive at all. Totally blank. Windows shows:

Used Space: 236,106,571,776 bytes
Free Space: 2,715,225,501,696 bytes
Capacity : 2,951,332,073,472 bytes

This is a brand new empty drive. Maybe this is normal and I'm just not aware. But a quarter of a TB is a lot of unreachable space. If I did the math right, that's like 8% of a 3TB disk. Upon further inspection, I find the other two volumes have the same percentage of missing space as well. 8% may not sound like much. But 250GB is a drive in itself. Is this basically SWAP space? Can this number be adjusted down any?

Thanks for your time,

Doug

 

[ben]

I suspect you're encountering the base2 vs base 10 discrepancy. Drive manufacturers list powers-of-10 drives sizes, but operating systems use powers of two. Since powers of two are larger, this means you're getting fewer bytes than you thought you were, and this divergence increases with the sizes of the drives.

 

[pirateghost]

http://www.ussscctv.com/harddrivesizecapacitiescalculator.aspx

 

[NebulaM57]

Just want to say thanks for everyone's input. If that's truly the numbers, then I guess that's life. lol

Thanks again!