dovecot - May 2021 - Dovecot v2.3.13 reporting (very) incorrect vsize for some maildir folders

> On 10 May 2021, at 11:52, Timo Sirainen <timo at sirainen.com> wrote:
> 
> S= is the "physical size", W= is the "virtual size".
quota=count / vsize calculations should be using the W= value, not the S= value.

I renamed all messages containing S= and W= values in a user's mailbox
(Trash) which had the incorrect quota calculation, stripping these from the
filenames to ensure they were not causing incorrect calculations.

Then, I deleted every single dovecot* file in the user's mailbox (all
indexes and control files, including dovecot-uidlist):

  root at server:~# find /mail/<username>/Maildir/ -type f -name
'dovecot*' -delete

Running `doveadm mailbox status -u <username> 'vsize'
'Trash'` -still-, even after all this, returns a vsize calculation that
is off by a factor of about two:

root at server:~# du -bs /mail/<username>/Maildir/.Trash
7200481589      /mail/<username>/Maildir/.Trash
root at server:~# doveadm mailbox status -u <username> 'vsize'
'Trash'
Trash vsize=14584428026

(The user was not logged in during any of this testing)

I am at a bit of a loss at what is causing this issue now. I have tested against
2.3.13 and 2.3.14 now. Any chance I may have hit a bug in these versions?

It is worth mentioning that I have only encountered a small handful of users
(out of about 100k) where the quota calculation is wildly incorrect. For the
most part it appears to be right.

- Eirik

> On 20/05/2021 13:16 Eirik Rye <rye at trojka.no> wrote:
> 
>  
> > On 10 May 2021, at 11:52, Timo Sirainen <timo at sirainen.com>
wrote:
> > 
> > S= is the "physical size", W= is the "virtual
size". quota=count / vsize calculations should be using the W= value, not
the S= value.
> 
> 
> I renamed all messages containing S= and W= values in a user's mailbox
(Trash) which had the incorrect quota calculation, stripping these from the
filenames to ensure they were not causing incorrect calculations.
> 
> Then, I deleted every single dovecot* file in the user's mailbox (all
indexes and control files, including dovecot-uidlist):
> 
>   root at server:~# find /mail/<username>/Maildir/ -type f -name
'dovecot*' -delete
> 
> Running `doveadm mailbox status -u <username> 'vsize'
'Trash'` -still-, even after all this, returns a vsize calculation that
is off by a factor of about two:
> 
> root at server:~# du -bs /mail/<username>/Maildir/.Trash
> 7200481589      /mail/<username>/Maildir/.Trash
> root at server:~# doveadm mailbox status -u <username>
'vsize' 'Trash'
> Trash vsize=14584428026
> 
> (The user was not logged in during any of this testing)
> 
> I am at a bit of a loss at what is causing this issue now. I have tested
against 2.3.13 and 2.3.14 now. Any chance I may have hit a bug in these
versions?
> 
> It is worth mentioning that I have only encountered a small handful of
users (out of about 100k) where the quota calculation is wildly incorrect. For
the most part it appears to be right.
> 
> - Eirik
Hi!

Quota will count only virtual size of mails (and not directories) and that will
likely never match with du -bs, which counts for things more than just the mail
contents.

Aki