Re: [exim] Exim, Dovecot, mdir and hardlinks - a true story

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Author: Andrew C Aitchison
Date:  
To: Jeremy Harris
CC: exim-users
Subject: Re: [exim] Exim, Dovecot, mdir and hardlinks - a true story
On Wed, 14 Aug 2019, Jeremy Harris via Exim-users wrote:

> On 14/08/2019 12:37, Andrew C Aitchison via Exim-users wrote:
>> I suspect an option to have a fast but inaccurate quota would be useful
>> in some circumstances.
>
> We already have maildir_use_size_file; rebuilding isn't needed often.
>
> Do we need a fast/poor quota method for cases where the size-file
> cannot be used?


Ah. I had missed that Cyborg is using maildir format (I'm used to mbox).

> Other possible ways of balancing: we currently glance at the filename,
> trying to pull a size encoded in it. That saves an additional per-file
> stat call to get the size. But without the stat we don't have an
> inode number... we can hash the filename, but that only works if
> a hardlink is to a different dir but with the same name. We could
> glance at the number of links, and only bother remembering >1 link
> nodes - but, again, we then need to do the stat call.


>From the introduction to "Chapter 26 - The appendfile transport":

Exim recognizes system quota errors, and generates an appropriate
message. Exim also supports its own quota control within the transport,
for use when the system facility is unavailable or cannot be used for some reason.

Now I think about it I've not (knowingly) used both on the same filesystem.
I also now realize that the INBOX and the files that a .forward file
redirects mail to may be on different disks and have different quotas ...

-- 
Andrew C. Aitchison                    Kendal, UK
             andrew@???