connrejectthreshold MMP option specifies the number of connections to accept before rejecting client connections with a soft error at connection time. The default value is computed based on the operating system file descriptor limits for the MMP server process, or 2000 if such file descriptor limits can not be determined. If this is set too high, connections can fail with a '
Too many open files' error.
The default calculation is the file descriptor limit minus 64 (to leave space for log files, LDAP connection pools, internal pipes, etc) divided by 2.