CentOS - Dec 2005 - Planning Mail Server (with low resources)

Hello,

I'm planning the installation of the school's Mail Server. This is the
first time I get in administration. I've been reading about postfix,
cyrus  and the first page in the guide of HughesJR.com[2] about
installing postfix-cyrus, but due my low hardware resources, I ask for
suggestions to see If what I need can be done (and|or) stable.

Hardware:
Pentium III 1.4Ghz
256 RAM
40 GB HD-IDE

Soft:
CentOS 4.2
Postfix
Cyrus-IMAPd
MailScanner
Spanassassin

Partitioning(in MB)[1]:
/                                   1.000
/boot/                            100
/home/                          15.000
/swap/                           512
/tmp/                             500
/usr/                              1.000
/var/                              5.000
/var/log/                         2.000
/var/spool/mail/               14.800

The server will serve around 2000 students, but only 80(maybe 100)
concurrent at time. I would like to make a very basic installation,
'cause as you can see, I am with a very low hardware resources. This
host will be mail dedicated.

In the near future the hard would be upgraded(maybe a nu computer).
Now, I need something to show in a working environment.

I'll appreciate any suggestion.

I've never been involved in this. I used to program with php, but now,
it has been delegated :| to me (chosen between other tasks).

Some orientation (and|or) readings will be great too, even while, I'll
continue reading about partitioning[3] (think my first step).

thanks in advanced for your time.

[1] http://www.linuxsa.org.au/tips/disk-partitioning.html
[2] http://www.hughesjr.com/content/view/9/30/Guides
[3] http://www.tldp.org/HOWTO/Partition/intro.html

On Mon, 2005-12-05 at 21:26 -0500, Alain Reguera wrote:
> Hello,
> 
> I'm planning the installation of the school's Mail Server. This is
the
> first time I get in administration. I've been reading about postfix,
> cyrus  and the first page in the guide of HughesJR.com[2] about
> installing postfix-cyrus, but due my low hardware resources, I ask for
> suggestions to see If what I need can be done (and|or) stable.
> 
> Hardware:
> Pentium III 1.4Ghz
> 256 RAM
> 40 GB HD-IDE
> 
> Soft:
> CentOS 4.2
> Postfix
> Cyrus-IMAPd
> MailScanner
> Spanassassin
> 
> Partitioning(in MB)[1]:
> /                                   1.000
> /boot/                            100
> /home/                          15.000
> /swap/                           512
> /tmp/                             500
> /usr/                              1.000
> /var/                              5.000
> /var/log/                         2.000
> /var/spool/mail/               14.800
> 
> The server will serve around 2000 students, but only 80(maybe 100)
> concurrent at time. I would like to make a very basic installation,
> 'cause as you can see, I am with a very low hardware resources. This
> host will be mail dedicated.
> 
> In the near future the hard would be upgraded(maybe a nu computer).
> Now, I need something to show in a working environment.
> 
> I'll appreciate any suggestion.
> 
> I've never been involved in this. I used to program with php, but now,
> it has been delegated :| to me (chosen between other tasks).
> 
> Some orientation (and|or) readings will be great too, even while, I'll
> continue reading about partitioning[3] (think my first step).
> 
> thanks in advanced for your time.
> 
> [1] http://www.linuxsa.org.au/tips/disk-partitioning.html
> [2] http://www.hughesjr.com/content/view/9/30/Guides
> [3] http://www.tldp.org/HOWTO/Partition/intro.html
----
looks good but /usr is way too small. /usr is gonna need probably more
like 3.5 Gigabytes

Suggest you consider having separate partitions for 
/boot 
/home
/tmp
/var/spool/imap # cyrus would default to this
swap
and combine the rest in / which allows fluctuation for /usr and /var
usage - perhaps maybe 8 gigabytes.

Craig

Alain Reguera wrote:
>Hello,
>
>I'm planning the installation of the school's Mail Server. This is
the
>first time I get in administration. I've been reading about postfix,
>cyrus  and the first page in the guide of HughesJR.com[2] about
>installing postfix-cyrus, but due my low hardware resources, I ask for
>suggestions to see If what I need can be done (and|or) stable.
>
>Hardware:
>Pentium III 1.4Ghz
>256 RAM
>40 GB HD-IDE
>
>Soft:
>CentOS 4.2
>Postfix
>Cyrus-IMAPd
>MailScanner
>Spanassassin
>
>Partitioning(in MB)[1]:
>/                                   1.000
>/boot/                            100
>/home/                          15.000
>/swap/                           512
>/tmp/                             500
>/usr/                              1.000
>/var/                              5.000
>/var/log/                         2.000
>/var/spool/mail/               14.800
>
>The server will serve around 2000 students, but only 80(maybe 100)
>concurrent at time. I would like to make a very basic installation,
>'cause as you can see, I am with a very low hardware resources. This
>host will be mail dedicated.
>
>In the near future the hard would be upgraded(maybe a nu computer).
>Now, I need something to show in a working environment.
>  
>
That is PLENTY fast enough to run the mail server that Johnny talks 
about in his web pages as long as people have relatively small mailbox 
quotas.  One change would be to add more memory to the machine if you 
can (memory is cheap these days so that might not even be an issue).  
I'd suggest a gig of RAM and a gig of swap.  IDE disks are also cheap so 
it might be better to upgrade it to something like a 300 or 400gig drive 
now than to wait until you run out of space in the very near future.

Cheers,

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On Mon, Dec 05, 2005 at 09:26:04PM -0500, Alain Reguera
wrote:
> Hello,
> 
> I'm planning the installation of the school's Mail Server. This is
the
> first time I get in administration. I've been reading about postfix,
> cyrus  and the first page in the guide of HughesJR.com[2] about
> installing postfix-cyrus, but due my low hardware resources, I ask for
> suggestions to see If what I need can be done (and|or) stable.
> 
> Hardware:
> Pentium III 1.4Ghz
> 256 RAM
> 40 GB HD-IDE
> 
> Soft:
> CentOS 4.2
> Postfix
> Cyrus-IMAPd
> MailScanner
> Spanassassin
First off, dump either antivirus or antispam on that machine. You
don't have enough memory to keep both happy.

A P3 1.4GHz is more than up to the task, so you will have no problem there.

You might also want to change Cyrus-imapd to something simpler, like
wu-imapd, since it should take less resources from the machine. Then again,
I have very little experience with cyrus, since I either use wu or courrier.

[]s

- -- 
Rodrigo Barbosa <rodrigob at suespammers.org>
"Quid quid Latine dictum sit, altum viditur"
"Be excellent to each other ..." - Bill & Ted (Wyld Stallyns)

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From: Alain Reguera [mailto:alain.reguera at gmail.com]
> 
> guys thanks for the fast replays
> 
> Then, restructuring the mail-box:
> 
> Hardware:
> Pentium III 1.4Ghz
> 256 RAM
> 40 GB HD-IDE
> 
> Soft:
> CentOS 4.2
> Postfix
> (Cyrus-IMAPd|wu-imapd|courrier)
> MailScanner [moved]    \ [1]
> Spanassassin [moved]  /
> 
> Partitioning(in MB):
> /                         8.000
> /boot/                  100
> swap                   512
> /home/                14.888
> /tmp/                   500
> /var/spool/imap/    2.000 # This could be as a Cyrus Swap, moreover of
> System Swap?
> /var/spool/mail/     14.000
> 
> [1] To somewhere else where the mail box connect before sending and
> receiving mails to check for, or maybe another tricky configuration?.
> :)
I will second the recommendation to increase your RAM to 1 GB.
SpamAssassin tends to use lots of RAM.  As long as you can keep it out
of swap, it runs great, but as soon as it runs out of memory and
starts swapping, your performance will drop like a rock and probably
cause mail to start piling up.

Your machine should be fast enough to run ClamAV and SpamAssassin
locally, as long as you increase the RAM.

Bowie

Alain Reguera wrote:
> Hello,
> 
> I'm planning the installation of the school's Mail Server. This is
the
> first time I get in administration. I've been reading about postfix,
> cyrus  and the first page in the guide of HughesJR.com[2] about
> installing postfix-cyrus, but due my low hardware resources, I ask for
> suggestions to see If what I need can be done (and|or) stable.
> 
> Hardware:
> Pentium III 1.4Ghz
> 256 RAM
> 40 GB HD-IDE
I'm running something similar (sendmail vs. postfix, mimedefang vs. 
mailscanner) on much slower machine (but also, with much less users).
> /var/spool/mail/               14.800
Cyrus uses /var/spool/imap for mail storage.  So you might want to 
change the above to /var/spool/imap.
> The server will serve around 2000 students, but only 80(maybe 100)
> concurrent at time. I would like to make a very basic installation,
> 'cause as you can see, I am with a very low hardware resources. This
> host will be mail dedicated.
For the number of users, you'd probably want to consider dual-CPU 
system.  Also, unless you impose mailbox quotas (trivial to do with 
cyrus), you'll run out of disk space relatively fast (for that number of 
users).  Remember, with IMAP, mail is stored on the server.  Disk is 
cheap nowdays, get yourself two 250MB drives ($150-200 investment) and 
make software RAID-1.  You'll get both capacity and redundancy.

Your hardware specs exceed that of the box that was serving mail to
*more* students about 8 years ago at Duke University.  That box, if
memory serves, was a Pentium 90MHz running Solaris x86.  Though it did
have the benefit of SCSI disks.

If you can serve only POP3 instead of IMAP, that box will have no
problem serving that many users and more.

If you're going to do IMAP, I suggest trying out Dovecot and doing some
comparative benchmarks before you settle on Cyrus.   I made the switch
on a dual Pentium III 800MHz box, 256MB RAM, 20GB disk, and the
performance difference was staggering.  

I agree with using Postfix instead of Sendmail.

Some of the other things like virus scanning and spam filtering is
something the old Duke mail server never had to worry about, and
admittedly that adds a big unknown into the equation.

I'll echo the sentiments of the other folks and say that /usr needs to
be bigger.  Also, I highly recommend putting everything but /boot into
LVM so that you can take advantage of more disk later on.