Re: [Exim] Washington mbx again

On Mon, 2 Oct 2000 exim-users@??? wrote:

...
> > We also backup everything using Legato, and if each mail occupies one
> > file, then the index will be very very big. On the other hand mbx
> > format will just have one file/user and the index will not be that big.
>
> But then you end up with performance hits as the MTA does seeks on
> huge files, as does your MUA. Aswell as the down side of file corruption.
> I much prefer maildir for the fact that it's 5 step delivery proceedure
> is much nicer to the very broken NFS, and give you a much better chance
> of no data loss over crashes etc etc.

Seeks are seeks. It doesn't matter what you are seeking to, as the
average seek time is the same. The number of seeks required with MBX are
MailDir should roughly identical (about 1 seek per message), because I
really doubt that you'd have much luck of having two MailDir messages
stored in the physical disk back to back.

> > I have noticed that using standard Unix mailbox format, swap space used
> > by individual user is directly related to the mailbox (inbox/folder)
> > size. Is the same with mbx format? How does maildir uses the swap
> > space?
>
> I think mbx is a proprietary file format, but doesn't differ much in
> terms of size to berkley format - I may be wrong. Depending on how your
> MUA works, using maildir you generally stand a better chance of better
> (less) memory usage (a mails body is read when needed) from a seperate
> file, as opposed to loading a massive file, or seeking.

MBX is not propietary. It is a indexed version of mbox.

Memory usage depends on the implemenation. There is usually a tradeoff
for memory usage vs. performance that developers make.

> Although of course if several thousand users read mail and the MUA
> cp's the mail folder to a temp file in /var, you're going to have to
> make sure you have the space for it,
>
> Have Fun!
>
> D.


Tom