This morning found under heavy I/O delay.
Try check it out by:
free -m vmstat 1 top wa --order by wait I/O
The Postfix qmgr process causes heavy overload, which doesn't make any sense to me.
Have to check the mail queue.
mailq | wc -l
which give me over 40K queued emails.
by reading them, here is same example:
Message 2: From root@PRODUCTION.localdomain Thu Feb 2 16:41:01 2018 Return-Path: <root@PRODUCTION.localdomain> X-Original-To: root Delivered-To: root@PRODUCTION.localdomain From: root@PRODUCTION.localdomain (Cron Daemon) To: root@PRODUCTION.localdomain Subject: Cron <root@PRODUCTION> /usr/local/check_status.pl Content-Type: text/plain; charset=UTF-8 Auto-Submitted: auto-generated X-Cron-Env: <SHELL=/bin/bash> X-Cron-Env: <PATH=/sbin:/bin:/usr/sbin:/usr/bin> X-Cron-Env: <MAILTO=root> X-Cron-Env: <HOME=/> X-Cron-Env: <LOGNAME=root> X-Cron-Env: <USER=root> Date: Thu, 2 Feb 2018 16:41:01 -0400 (EST) Status: RO
It turn's out that one of the cron job runs every minute did not have a proprietary MAIL to settings.
Before: MAILTO=root HOME=/ * * * * * root /usr/local/check_status.pl I changed after: MAILTO="" HOME=/ * * * * * root /usr/local/check_status.pl >/dev/null 2>&1
Then purge all old emails both postfix queue and local mail:
$ postfix -d ALL $ mail & delete * & q
Just want make it more clean, I try to remove the postfix package:
# chkconfig # service postfix status # service postfix stop # chkconfig postfix off # chkconfig # yum erase postfix But it also want remove cronie cronie-anacron crontabs Which I still want it.
The cron require at lease one MTA on system.
Because we had smart host Email internal.
I did install my favorite SSMTP inside of sendmail.
First Backup the /etc/postfix
# cp -r /etc/postfix ~/etc_postfix_backup # yum install ssmtp # yum erase postfix
Setup the /etc/ssmtp/ssmtp.conf, did small test.
Everything looks good.
Please notice the server is not serve as an EMail server.
Reference:
