move from mbox to Maildir?

[Rashkae]

On 11/04/2011 08:44 PM, Noah wrote:
> Hi there,
>
> I have problems with a lot of memory needed for indexing my mbox by 
> dovecot and wondering if I transitioned from mbox to Maildir if that 
> would help with the indexing processing?  If so is there a good 
> tutorial for moving postfix from mbox to Maildir?
>
> Cheers,
>
> Noah
>

Hi Noah.

I've not tested Dovecot memory usage between mbox and maildir, and there 
might be factors I'm not considering that affect this other than I 
expect.  However, I don't think you'll see much difference, and 
potentially, much worse performance with maildir in this regard.

Consider that to create a new index of a Maildir directory, dovecot 
would have to open and read each and every file, potentially 10's of 
thousands, individually to scan the contents and add to the index.  
Incidentally, this is also what happens when you do a search for 
something within the bodies of the e-mail (as opposed to searching 
within the indexed headers.)

The big advantage to Maildir is that deleting messages, or moving 
messages from one folder to another, does not require the system to 
re-write the entire contents of the mail folder.  It can also be much 
easier on backup systems, since only new mail messages would have to be 
copied, (vs copying the entire contents of the mail folder each time.)