On Thu, Jan 25, 2018 at 03:50:24PM -0500, Tech Gurus wrote:
> I have single mail server that send relatively large amounts of emails at
> least 3 times a day ranging from 15K to 50K each time ..
This is in general terms not a lot of mail for Postfix to handle.
Medium volume Postfix servers run at a leisurely sustained pace of
around 10--20 msgs/sec handling around 1--2 million messages a day.
High volume Postfix servers handle well north of 100 msgs/sec,
handling 10s of millions of messages a day.
> 80% of emails are going to one domain owned by my company *(Domain1)*.. The
> current mail flow does around 1K-1.2K per minute , this is CentOS 7 VM ( 4
> CPU/8GB Memory) running on SSD Datastore.
1200/minute is 20/sec, so this is a modest though not low message
rate. If your system is not going any faster despite a backlog of
mail to send, most likely the problem is on the receiving side.
You can't deliver any faster than the rate at which the receiving
system is able to accept mail.
So first find out whether the receiving system is running at full
capacity. If not, try to understand is how long each delivery
takes, and what your concurrency settings are. You can't tune a
system blind-folded, nor anyone help you without any quantitative
information about the mail flow. You'll need to understand the
distributions of the "delays=a/b/c/d" data in your logs. In
particular throughput is largely determined by your concurrency
divided by the typical "c+d" value.
> - Changed default_destination_concurrency_limit to 100 and
If raising concurrency is not helping much then the destination is
likely saturated or you have network bandwidth problems.
> default_destination_recipient_limit = 1500
For both parameters, instead of changing the numbers for all
destinations, configure a dedicated transport for the congested
destination, and adjust the variables just for that:
foo_destination_concurrency_limit = 100
foo_destination_recipient_limit = 1500
with "foo" a clone of the "smtp" or "relay" transport definition
in "master.cf".
--
Viktor.
