URGENT help needed with Postfix which stopped working on 11 Jan 2025 Saturday at about 3.00 AM

SYSTEM INFORMATION
OS type and version AlmaLinux 9.5
Webmin version 2.202
Virtualmin version 7.30.4
Webserver version 2.4.62
Related packages Postfix

Subject: URGENT help needed with Postfix which stopped working on 11 Jan 2025 Saturday at about 3.00 AM

Dear Virtualmin and Webmin community,

I have stopped receiving emails since 11 Jan 2025 Saturday at about 3.00 AM.

I tried rebooting my AlmaLinux 9.5 Virtual Private Server (VPS) and restarting Postfix but to no avail.

Whenever I try to start Postfix, the service would be killed by the OOM Killer almost immediately.

Running “systemctl status postfix” shows oom-kill.

When I checked /var/log/messages, many related services were also killed by the OOM Killer.

But this is strange. This should not be happening at all because I have 8 GB of physical memory for my VPS.

But I do notice there were 100+ messages inside the Postfix message queue. Did my email account(s) get compromised by hackers?

Then I tried uninstalling the Postfix package and reinstalling Postfix from within Virtualmin.

After doing this, there were no more oom-kill error messages but Postfix is still not working!

I suspect that all the Postfix configuration was lost after uninstalling and reinstalling. The message queue was also reduced to zero.

Before flying to Seoul, South Korea on 7 Jan 2025 Tuesday, I had made a backup of all Virtual Servers and all Virtualmin settings on 5 Jan 2025 Sunday.

Inside the backup archive “virtualmin.tar.gz”, I have the following backup files.

Volume in drive E is Local Disk
Volume Serial Number is 287E-92C9

Directory of E:\temp

13/01/2025 05:16 PM .
13/01/2025 05:16 PM 0 filelist.txt
05/01/2025 10:46 PM 0 virtualmin_chroot
05/01/2025 10:46 PM 8,615 virtualmin_config
14/12/2022 04:45 PM 0 virtualmin_custom
14/12/2022 04:45 PM 0 virtualmin_custom_linkcats
14/12/2022 04:45 PM 0 virtualmin_custom_links
05/01/2025 10:46 PM 0 virtualmin_custom_shells
05/01/2025 10:46 PM 20,480 virtualmin_email
05/01/2025 10:46 PM 2 virtualmin_mailserver
05/01/2025 10:46 PM 135 virtualmin_mailserver_dkim
21/10/2021 08:57 PM 1,679 virtualmin_mailserver_dkimkey
05/01/2025 10:46 PM 20 virtualmin_mailserver_grey
22/09/2016 04:09 PM 9,666 virtualmin_mailserver_greyclients
22/09/2016 04:09 PM 188 virtualmin_mailserver_greyrecipients
31/12/2024 05:26 PM 30,146 virtualmin_mailserver_maincf
23/11/2023 02:10 PM 6,408 virtualmin_mailserver_mastercf
05/01/2025 10:46 PM 20 virtualmin_mailserver_ratelimit
02/02/2022 01:38 AM 5,592 virtualmin_mailserver_ratelimitconfig
05/01/2025 10:46 PM 10,240 virtualmin_scheds
05/01/2025 10:46 PM 10,240 virtualmin_scripts
05/01/2025 10:46 PM 20,480 virtualmin_templates
14/12/2022 04:45 PM 0 virtualmin_templates_global
05/01/2025 10:46 PM 10,240 virtualmin_templates_plans
05/01/2025 10:46 PM 10,240 virtualmin_templates_skel_0
24 File(s) 144,391 bytes
1 Dir(s) 641,303,912,448 bytes free

How should I go about restoring the Postfix configuration which was lost after uninstalling and reinstalling?

Please advise.

Thank you very much.

Regards,

Mr. Turritopsis Dohrnii Teo En Ming
Targeted Individual in Singapore
13 Jan 2025 Monday 5.26 PM

Hi,

My Postfix service is now working after I restored main.cf and master.cf Postfix configuration files from the backup archive “virtualmin.tar.gz”.

I can now receive emails.

May I know which other configuration files I would need to restore from the backup archive “virtualmin.tar.gz”??? In case I miss out something.

Please advise.

Thank you.

Regards,

Mr. Turritopsis Dohrnii Teo En Ming
Targeted Individual in Singapore
13 Jan 2025 Monday 6.00 PM

Maybe run Recheck configuration, and see if you get errors.

This is always a bad instinct. Nothing good can happen.

You need to find out why it’s happening. OOM is a catastrophic event, something bad has to happen. There are no alternatives when processes need to allocate memory and don’t have memory to allocate. So, it is urgent that you figure out why you’re running out of memory before you start trying to solve it. You can’t solve what you don’t understand.

Postfix was likely not even the offending process (the OOM killer doesn’t necessarily kill the largest process, it kills the one that its heuristics think is least important at the moment), so you may be fighting with the wrong thing.

Dear Joe,

I am not sure why OOM Killer is killing Postfix and a few other related services.

But I have got Postfix working now after restoring 2 configuration files: main.cf and master.cf. I have only restored these 2 configuration files.

Please let me know if I need to restore any other Postfix configuration files. Please refer to the list of backup files below.

05/01/2025 10:46 PM 0 virtualmin_chroot
05/01/2025 10:46 PM 8,615 virtualmin_config
14/12/2022 04:45 PM 0 virtualmin_custom
14/12/2022 04:45 PM 0 virtualmin_custom_linkcats
14/12/2022 04:45 PM 0 virtualmin_custom_links
05/01/2025 10:46 PM 0 virtualmin_custom_shells
05/01/2025 10:46 PM 20,480 virtualmin_email
05/01/2025 10:46 PM 2 virtualmin_mailserver
05/01/2025 10:46 PM 135 virtualmin_mailserver_dkim
21/10/2021 08:57 PM 1,679 virtualmin_mailserver_dkimkey
05/01/2025 10:46 PM 20 virtualmin_mailserver_grey
22/09/2016 04:09 PM 9,666 virtualmin_mailserver_greyclients
22/09/2016 04:09 PM 188 virtualmin_mailserver_greyrecipients
31/12/2024 05:26 PM 30,146 virtualmin_mailserver_maincf
23/11/2023 02:10 PM 6,408 virtualmin_mailserver_mastercf
05/01/2025 10:46 PM 20 virtualmin_mailserver_ratelimit
02/02/2022 01:38 AM 5,592 virtualmin_mailserver_ratelimitconfig
05/01/2025 10:46 PM 10,240 virtualmin_scheds
05/01/2025 10:46 PM 10,240 virtualmin_scripts
05/01/2025 10:46 PM 20,480 virtualmin_templates
14/12/2022 04:45 PM 0 virtualmin_templates_global
05/01/2025 10:46 PM 10,240 virtualmin_templates_plans
05/01/2025 10:46 PM 10,240 virtualmin_templates_skel_0

Thank you.

Regards,

Mr. Turritopsis Dohrnii Teo En Ming
Targeted Individual in Singapore
14 Jan 2025 Tuesday 5.52 PM