We have a Web server with Windows Server 2008 OS, SQL server 2008 & Mailenable (free version) for SMTP.
We are scheduling jobs to send out emails daily to members (around 20,000 emails) & We are sending out newsletters to members weekly (150000 members). The server goes down 50% of the time when the scheduled jobs run & almost 90% of the time when we send out our newsletter.
Since we thought SMTP server is unable to handle the load, we created a job to send out 5000 emails per hour with a time lag of around 5 seconds after every 20 emails being sent. Initially, the server responded well & server going down reduced very much. But for the next couple of weeks we are facing the same problem.
We have plesk also in the server. So I assume OS, IIS, Plesk, mailenable & SQL are all participants in the mailing process.
Have any of you faced such issues. Any suggestions are welcome.
Thanks in advance.