Re: [Exim] Washington mbx again

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Szerző: Paul Robinson
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Címzett: Sujit Choudhury, exim-users
Tárgy: Re: [Exim] Washington mbx again
On Mon, 02 Oct 2000, 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+?


Should be fine, but you would be well advised to split the users across
several directories, and ideally each of these directories should be mounted
off different disks. The performance increase is worth the time take to get a
few extra drives working in a machine.

Maildir will also generally be faster on delivery, pickup, use less memory on
large spools, etc. so in general is a Good Thing, but you have to remember
that your users need to be able to pick the mail up, so if they are POP3'ing
in, they you are limited to the POP3 daemons you can use (personally, I would
pay large wedges of cash for qpopper to be able to do maildir natively), and
the same can be said for any mail pickup system - delivering mail to the mail
spool on the server is only half the battle. ;-)

> 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.
> 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?


Hmmm. Perhaps I am mis-reading something here, but I can't see how swap space
usage is determined from mailbox usage. I take it we're talking about proper
Unix virtual memory, and not just some files being moved around? Swap space
usage is determined by the VM policy of the underlying operating system - for
example, Linux tries to avoid using swap at all costs, *BSD will swap out
processes that have been idle for "X" amount of time, etc.

Or am I missing something obvious here? (I've got flu, OK?) :-)

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