Inaccurate free disk space

[awesir]

Hi, I have a 2x2TB ext4 RAID 1 setup on a DNS 320 and the amount of disk space on the web interface and reported to Windows SMB appears to be higher than what I know the files to be. It will lower with use but not by much. 

[Joao Cardoso]

On Wednesday, June 24, 2020 at 10:26:50 PM UTC+1, awesir wrote:

Hi, I have a 2x2TB ext4 RAID 1 setup on a DNS 320 and the amount of disk space on the web interface and reported to Windows SMB appears to be higher than what I know the files to be. It will lower with use but not by much. 

Disk manufactures uses MB as 1 000 000 bytes, GB=10⁹, etc (base number 10) . Filesystems use MiB, 1024*1024 = 1048576, GiB, 1024*1024*1024 = 1073741824, etc (base number 2). Network guys and utilities often report bits, thus 1Mb/s is not 1MB/s nor 1MiB/s.

Alt-F just display the figures the disks or filesystem utilities say and append the generic MB, GB, TB, thus the difference. A 3TB disk appear as having a 2.7TiB filesystem.