Postfix not sending all emails generated from mailx command
 

We are running RHEL 6.2. Our ERP system runs a program that emails invoices to our customers. There can be 300+ generated within a few seconds. We are using postfix and the emails are generated using the mailx command. It appears that all emails after the 294th one are not being sent. I've reviewed the /var/log/maillog file and have searched for specific email addresses after the 294th one and they aren't in there.

We are logging all output from the mailx command in case there were any errors generated, but there have not been any. Has anyone run into a similar issue or have any suggestions on where to look or what might be causing this issue?

Any assistance is much appreciated.

Regards,
Nancydrew72

possible workaround
 

I would first consider a workaround suggested by the problem: If you can create a wrapper or script replacement for mailx so that 290 mails are sent then restart a separate instance to handle the next 290 mails until all mails are sent. Might give you some time to handle the problem more elegantly. Next: look at the code for postfix and see if there is any hard limit set for any counters in the code that might be responsible for your problem. GOOD LUCK.

Thank you for the suggestion. I opened a ticket with Red Hat regarding this issue and so far we've found there is no limitation that would cause this. Also, we turned on auditd and found that although the program generating the mailx commands shows its sending them they are not being executed (at least not when it gets down to the last 90 or so, but it varies based on the number we are sending).

I've been monitoring at what point the emails stop and at first it was the 294th email, but since then it seems to vary. Any suggestions for an alternate service to send emails with?

I did a little research and per your question about what to use to send mail check the link: http://tecadmin.net/ways-to-send-ema...-command-line/ and try "mutt" and "ssmtp" as examples. You could also look into something like "majordomo" but that requires a learning curve.

I also think that if you feel that determining why the "sendmail" is failing you could use "strace'. I hope this is of some help.