Problem in running Qmail on peak traffic !!!

Dear All

I am setting up a HA cluster with following
configurations.


One Linux File Server with NFS share of Qmail with
vpopmail,courier imap and Mysql , One postgresql
Database Server


Two HA nodes , node1 and node2 running in Active
Passive setup with NFS shared directories from Linux
File server


Totally three machines are there in the setup.


The server was setup and made active . There are some
900 client users connecting to this server for POP3
mail fetching ,

and some 30 concurrent users connecting to postgres
database.

Some 300 users concurrently connect and mail at Peak
time with an average of 100 MB size of traffic .


The node1 configuration is a PIII 733 MHz with 512 MB
DDR Ram .

The node2 configuration is same as node1.

The Linux File server configuration is an HP Machine
with SCSI HDD. having PIII 733 MHz processor and 750
MB RAM.



I faced the following problems when server was made
live.

1) During Peak time of mail traffic, qmail - smtpd and
qmail - pop3d is not responding.,.No outlook clients
can establish a connection with mail server.

Only after restarting qmail, mail processing
continues.

This happens only during peak traffic.

2) NFS Stale error also comes during peak traffic,
when NFS requests becomes high.

On restarting the node1 of HA Cluster , NFS becomes
OK.


3) Memory utilisations shoots to 99% at peak times.


Please let me know what qmail patches i need to apply
for handling more than 800 concurrent pop requests
and some 100 concurrent mails in queue.

Regds

krishnan

In article <1127133921.264234.322990@z14g2000cwz.googlegroups .com>, Krishnan wrote:
> Dear All
>
> I am setting up a HA cluster with following
> configurations.
>
>
> One Linux File Server with NFS share of Qmail with
> vpopmail,courier imap and Mysql , One postgresql

I think you're going to have a hard time running
Qmail with /var/qmail/queue on an NFS volume.
Qmail does a performance trick by referring to files
by their inode numbers rather than their names.
It also depends on certain file system operations being
atomic.
Try running it on a local file system instead.
Mount it noatime for a small performance win.
Make sure there's enough RAM to cache the /var/qmail/queue
directory structure. If Qmail's the biggest thing happening
on the machine that's automatic.
Try recording the log on another machine, for another
small performance win, and of course your virus/spam
filter should be elsewhere.

Cameron

Thanks for your reply. i will make /var/qmail/queue and also
/var/qmail on local filesystem and run the mail server. The current
RAM is 512 and i will increase it to 1 GB. But i am still confused
how to run the Virus/spam filter?. Is it possible to run the virus/spam
filter on another machine, for eg:node2 of cluster which is passive
and process the mails.

Thanks for your reply. i will make /var/qmail/queue and also
/var/qmail on local filesystem and run the mail server. The current
RAM is 512 and i will increase it to 1 GB. But i am still confused
how to run the Virus/spam filter?. Is it possible to run the virus/spam
filter on another machine, for eg:node2 of cluster which is passive
and process the mails.?

kindly advise

Krishnan

Krishnan wrote:
> Thanks for your reply. i will make /var/qmail/queue and also
> /var/qmail on local filesystem and run the mail server. The current
> RAM is 512 and i will increase it to 1 GB. But i am still confused
> how to run the Virus/spam filter?. Is it possible to run the virus/spam
> filter on another machine, for eg:node2 of cluster which is passive
> and process the mails.
>

At what stage of the process is your anti-virus/anti-spam process kicks in?

Do you have the anti-spam/anti-virus process occur during the SMTP session.

In the original post you stated that you have the home directories setup
in NFS.

You might be better off separating the pop/imap portions to a POP
toaster. I.e. it will be an identical setup to your live servers, but
will only provide user access.
The smtp servers need not be in a cluster. If they are setup
identically, you should make all live since the storage space is NFS.

Not specifically familiar with the setup and what benefits they provide,
you might need to alter the version of NFS protocol your systems use
to mount the NFS share. Try protocol 3 (tcp) versus 2(UDP) or something
like that. the stale session is common with a Linux. I think there is
a need to add a certain tool/program that helps NSF maintain state. Do
a search for NFS stale file handle and Linux on your favorite search engine.

I think it uses rpc.statd or lockd in conjunction with nfsd.

AK

AK

Krishnan wrote:

> Thanks for your reply. i will make /var/qmail/queue and also
> /var/qmail on local filesystem and run the mail server. The current
> RAM is 512 and i will increase it to 1 GB. But i am still confused
> how to run the Virus/spam filter?. Is it possible to run the virus/spam
> filter on another machine, for eg:node2 of cluster which is passive
> and process the mails.?
>
> kindly advise
>
> Krishnan
>

It all depends on your setup. How does the anti-virus/spam mechanism
work in your setup? Without the answer to the prior question, there is
no way to answer your question because there is not enought information.

AK

I am running antivirus/ spam filter on the active node of HA cluster.
If i am running it on another linux server on same network, how is it
possible for me to scan the mails in the queue? will relaying the mail
through
that machine will help or i have to adopt any other method.


regds

Krishnan

Krishnan wrote:

> I am running antivirus/ spam filter on the active node of HA cluster.
> If i am running it on another linux server on same network, how is it
> possible for me to scan the mails in the queue? will relaying the mail
> through
> that machine will help or i have to adopt any other method.
>
>
> regds
>
> Krishnan
>

Krishnan,

At what stage of the process are the email messages scanned?

Is the Anti-virus/Anti-Spam filtering occur during the SMTP session or
does this process occur when the message is being delivered to the end user?

I saw your subsequent post. It seems that your anti-virus/spam process
occurs at the delivery.

Please provide the run file for the qmail-send process.

Provide what a user's .qmail or .procmailrc file contains.

AK