Hello,

I have two 3 Terabytes (GPT) partitions that show a huge difference in used data after a clean ext4 format. I am trying to understand why.

Partition 1, created on a physical 3TB disk shows 42GB used after clean format.
Partition 2, created on a 4 x 1TB raid5 array shows 201MB used after a clean format.

- Both partitions are almost identical in size.
- They have been created with identical commands.
- They have the same block size and amount of inodes.
- I did try all alignments types on the physical disk (parted -a; minimal, optimal, cylinder, none) but it does not make a difference.

Why?

* bump *

I am still trying to find an answer for this. Anybody?

Try diff'ing the output from "tune2fs -l" from both. May give a hint.

Thanks for your reply. Great suggestion, didn't think of that myself.

Unfortunately at present I do not have access to these configurations anymore. It might take a few months before I do. But it seems this is quite a common issue. I was hoping someone knew the answer.

If I get a chance again I will try your suggestion and report back here.