Re: [Exim] Washington mbx again

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著者: exim-users
日付:  
To: Sujit Choudhury
CC: exim-users
題目: Re: [Exim] Washington mbx again
Sujit Choudhury wrote:
> Can anybody tell me how maildir format would work in an environment
> where there are 20,000+ students and total mail coming to the system is
> about 50,000+?


Probably not too bad so long as you mailsplit it. Phil added some
support for splitting mail over multiple directories (I may be wrong
but I think the idea came from the layout we used here at Demon).

The idea being is that, yes you do get _some_ big directories, but
you dont end up with a MAMOTH directorty with everything in.

> 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.

> 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.

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.

-- 
    David Sloan - Senior Mail and News Systems Admin - Platform Management
  Tel: +44 845 272 0666    Fax: +44 20 8371 1167    Email: dsloan@???