How to increase iRedMail performance to process more emails? This is the question that has been harassing many iRedMail administrators.

 

I had been playing with iRedMail performance since 5+ years now. And still not thinking to discontinue it. If you haven’t tried your hands on this powerful mammoth of Email server, give it a try here: iRedMail Site. Start testing it and see how simple it is to install, configure and go live.

 

Creator and core developer of iRedMail (ZhangHuangbin) also has created beautiful, neat and easy to understand help documents. Following documents you can configure almost everything. iRedMail Document Site

 

I run my iRedMail performance server on following specs. This is far better or I would say excellent in terms of sending and receiving emails.  There is also another same specs server running as backup server which is replicated from primary server.

• Intel(R) Xeon(R) CPU E5-2640 0 @ 2.50GHz
• 20 GB DDR3 RAM
• 3 TB HDD with RAID 5
• CentOS Linux release 7.2.1511 (Core) - Minimal Install

Following is the list to check out on which I have applied various performance settings:

• Applied on iRedMail server - 0.9.5-1
• Current users on server - 850
• Current emails processing speed - 10,000+ per minute

Here you can follow these instructions to increase iRedMail performance.

 

Do not apply these settings directly on your production server. First understand each and every effects of these settings. If want to check, just apply it on any test server before going live.

 

First step is very simple, just setting up more concurrent Amavisd-new content filter processes. Default process limit is 2.

 

You can verify default process limit by hitting following command:

 

[root@mail ~]# cat /etc/amavisd/amavisd.conf | grep $max-servers
#$max_servers = 2; # num of pre-forked children (2..30 is common), 
# Do not notify administrator about SPAM/VIRUS from remote servers.
$max_servers = 2;

Let’s change default value to some higher. In my case I have applied 15 processes utilizing more CPU and RAM resources of my server which gives me best email processing performance.

 

Changing default value in amavisd also require change in postfix master.cf file having same value which you specify in amavisd.conf file.

 

Commands:

vi /etc/amavisd/amavisd.conf

Change following to your desired value:

# Num of pre-forked children.
# WARNING: it must match (equal to or larger than) the number set in
# /etc/postfix/master.cf "maxproc" column for the 'smtp-amavis' service.
$max_servers = 15;

Now change postfix master file to the same value:

vi /etc/postfix/master.cf

Change following value:

# Amavisd integration.
smtp-amavis unix - - n - 15 smtp

Once you complete above changes you must have to restart both amavisd and postfix services so that new changes takes effect.

 systemctl amavisd restart

systemctl postfix restart

All Done now…!!! Just start sending some emails and measure the performance. You can fine tune iRedMail performance with above changes as per email processing of your iRedMail server.