RE: [exim] Exim Performance / Server Performance

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Auteur: RootChaos
Datum:  
Aan: 'Phil Brutsche'
CC: exim-users
Onderwerp: RE: [exim] Exim Performance / Server Performance
Hi Phil

Thanx for the comments.

We are awaiting our new Dual P4 2.8 Xeon servers with 2 gigs of RAM and Raid
5 SCSI configuration as per your e-mail -- glad to see that we are basically
on par here... :)

As for the Qpopper. We will look at some alternatives when we install the
new hardware, thanx for those suggestions.

Can you perhaps provide some links to "The 1.0-stable tree of Dovecot" for
me to check out ??


Regards

RC


RootChaos wrote:
> Exim 4.30 (MySQL Database backend - Virtual Mailboxes) Amavisd-new
> F-PROT Antivirus Spamassassin Qpopper


Ugh. Qpopper.

> Hardware Config :-
>
> Dual Intel P4 2.8
> 2 GIG Ram
> 1 x 120 GIG IDE Hard Drive


Ugh. Single IDE hard drive.

I would replace Qpopper with something else - I prefer and recommend Cyrus
IMAP, but this is an existing installation with thousands of users and the
transition would require careful planning, to say the least.

Why is qpopper bad? See this link:
http://www.mailarchive.ca/lists/comp.mail.sendmail/2000-05/1783.html

I quote:

"The most likely bottleneck is qpopper I/O especially if your users have
large mailboxes that they are leaving on the server. qpopper copies the
entire mailbox from /var/mail to /var/pop (or wherever you've configured it
to go) for every POP connection."

The 1.0-stable tree of Dovecot should yield better performance and will be
able to serve your existing mailboxes.

As for the hard drive...

You would be well advised to redo your storage mechanism. You should have
*at least* a mirror for *everyting*. Your IMAP/POP3 storage would best be
placed on a RAID 10 or a RAID5 volume separate from the OS. EIDE/SATA or
SCSI is a decision I'll leave up to you.

Personally I would go 100% SCSI - 6 disks on a hardware RAID controller with
a decently-sized battery-backed cache: 2 mirrored for OS + 4 in RAID10 for
the data. I would also have a spare disk or two. Like I said, the decision
is up to you; other people will disagree with my recommendations.

--

Phil Brutsche
phil@???