[Dovecot] Purging a large folder... anything I need to be careful of?

Dennis Guhl dg at dguhl.org
Wed Feb 10 14:40:37 EET 2010

Charles Marcus schrieb:
> On 2010-02-10 12:59 AM, Dennis Guhl wrote:
>> Dave schrieb:
>>> I've got a large message folder (about 40G in 'cur') that I need to
>>> empty to a more reasonable size.  Oddly, my Thunderbird e-mail client
>>> only sees about 2.4G of that, and has "looped" a few times.  What I
>>> mean is, I thought someone was cleaning the folder out, but
>>> Thunderbird apparently was actually just looping back to 0 every 4
>>> gigs and starting to count up again  Ha.  But that's a sidenote.  So,
>>> since Thunderbird 
>> But it's a strange one.
>> I have some fairly big folders (>>10G) too but there is no problem at
>> all with TB
> Not entirely accurate. TB does indeed have a big problem with mbox files

Oh, I think that should be a bug, since today files with more then 
4GB are nor rare. But using only IMAP I never encountered this 
problem and wasn't aware of it.

> larger than 4GB. But as long as you don't set an IMAP folder that is
> larger than 4GB to full offline mode, you should be fine, BUT... the
> calculated size will be displayed using a 32-bit value, so as it
> calculates the size, when it hits 4GB, it will roll over and start again
> - so, a 6GB and a 10GB folder will both be displayed as 2GB...

OK, this I never observed. But there are no quotas on the folder so 
I never took a look at the size with TB.

>>> apparently is not seeing all of the messages,
> Yes it is - it is simply not calculating the folder size correctly. I
> don't know if this an underlying OS issue (32-bit vs 64-bit), or a TB bug...

And what is displayed as the message count if exceed 32 bit?

>>> what is the safest way
>>> to delete the files straight from the 'cur' folder?  IS that safe? 
>>> Will I mess up any of the dovecot indexes in any way??
>> Yes it is safe.
>> Dovecot has self healing abilities which will fix the index files.
> I don't think dovecots indexes are affected by this - it is merely a
> cosmetic TB issue.

When you go to ~/Maildir/cur/ to remove messages (as dave intend) 
dovecots indexes will indeed be affected. But it will cause no 
trouble beside throwing an entry in the log.

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