Re: load average question
On Sat, Nov 23, 2002 at 10:26:14AM +0100, Russell Coker wrote:
> On Sat, 23 Nov 2002 09:20, Torsten Krueger wrote:
> > Hmm - watch out for the load qpopper produces. Since the
> > sendmail/qpopper combination uses mbox a users mailbox is copied
> > every time the mbox is accessed. If you have large mailboxes (e.g.
> > no quota an users leave mail on server) this can produce a
> > significant load.
>
> You are correct, any pop server which uses mbox stores will cause very
> high system load, and qpopper is worse than some other pop servers.
>
> You and Craig are right about the benefits of Maildir.
that's partly true. it depends entirely on usage patterns, and not all
mbox pop daemons are as bad as qpopper. some are quite good.
for some usage patterns (i.e. large mailboxes left on the server on a
decent filesystem like XFS or reiserfs), Maildir is a clear winner.
for other usage patterns, the advantage isn't so clear - and in some
cases, it loses out to mbox. e.g. it's faster to open one file and read
it in one go than it is to have lots of little files, opening, reading,
and then closing them one-by-one.
Maildir does have some other advantages (e.g. it's NFS safe, and there
are no locking hassles*) so, all else being equal, it's a good choice to
make...but mbox isn't a bad choice either.
mbox is also, IMO, a lot more convenient than Maildir when you use mutt
(or elm, pine, etc) - it's easier to manipulate groups of mbox files
than Maildir directories with squillions of little files in them.
* mbox locking isn't a problem on debian systems anyway. all
programs that read or write mbox files conform to policy so locking
actually works reliably. still doesn't make mbox NFS-safe, though.
in short, if you can't choose between mbox and Maildir, then toss a
coin. whichever way it comes up will work fine :)
craig
--
craig sanders <cas@taz.net.au>
Fabricati Diem, PVNC.
-- motto of the Ankh-Morpork City Watch
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