What are the performance limitations of cfmail?
The highest throughput you can get is 400 emails per minute, based on the fact that the CF server spools 100 every 15 seconds to the mail server. That’s if you increase the spool setting from the default of 60 seconds from the Administrator. Also, there is a 65,535 message limit, based on the spool file naming convention. It appears that the files stored in the Spool directory are named using a hex naming convention of 0000.cfmail to FFFF.cfmail. When we recently sent more mails than the spool directory can handle (65535) the page crashed.
