On 20 May 2021, at 14:59, Timo Sirainen <timo@sirainen.com> wrote:

Well, next step could be to compare individual mail sizes. It would require writing some kind of a script to do the comparison though.

Hello again,

Apologies, I think dovecot is innocent in all of this.

I noticed that ls -s reported a completely different size to du, but similar to what dovecot reports:

ls -s | head -1

total 14099016

du

7050436 .

I assume there are some sparseness or block size related shenanigans going on here instead, causing differences in reported physical usage by du (syscall newfstatat()) compared to ls (syscall lstat()) and dovecot.

The filesystem quota system in Linux, which is what we're migrating from, apparently uses the same calculation method as du, which adds to the confusion.

• Eirik